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This article is about the metallic element. For the place, see Calcium, New York.
potassium ← calcium → scandium
Mg
↑
Ca
↓
Sr
Appearance
Dull gray, silver
General properties
Name, symbol, number calcium, Ca, 20
Element category alkaline earth metal
Group, period, block 2, 4, s
Standard atomic weight 40.078(4) g·mol−1
Electron configuration [Ar] 4s2
Electrons per shell 2, 8, 8, 2 (Image)
Physical properties
Phase solid
Density (near r.t.) 1.55 g·cm−3
Liquid density at m.p. 1.378 g·cm−3
Melting point 1115 K, 842 °C, 1548 °F
Boiling point 1757 K, 1484 °C, 2703 °F
Heat of fusion 8.54 kJ·mol−1
Heat of vaporization 154.7 kJ·mol−1
Specific heat capacity (25 °C) 25.929 J·mol−1·K−1
Vapor pressure
P/Pa 1 10 100 1 k 10 k 100 k
at T/K 864 956 1071 1227 1443 1755
Atomic properties
Oxidation states 2
(strongly basic oxide)
Electronegativity 1.00 (Pauling scale)
Ionization energies
(more)		 1st: 589.8 kJ·mol−1
2nd: 1145.4 kJ·mol−1
3rd: 4912.4 kJ·mol−1
Atomic radius 197 pm
Covalent radius 176±10 pm
Van der Waals radius 231 pm
Miscellanea
Crystal structure face-centered cubic
Magnetic ordering diamagnetic
Electrical resistivity (20 °C) 33.6 nΩ·m
Thermal conductivity (300 K) 201 W·m−1·K−1
Thermal expansion (25 °C) 22.3 µm·m−1·K−1
Speed of sound (thin rod) (20 °C) 3810 m/s
Young's modulus 20 GPa
Shear modulus 7.4 GPa
Bulk modulus 17 GPa
Poisson ratio 0.31
Mohs hardness 1.75
Brinell hardness 167 MPa
CAS registry number 7440-70-2
Most stable isotopes
Main article: Isotopes of calcium
iso NA half-life DM DE (MeV) DP
40Ca 96.941% 40Ca is stable with 20 neutrons
41Ca trace 1.03×105 y ε - 41K
42Ca 0.647% 42Ca is stable with 22 neutrons
43Ca 0.135% 43Ca is stable with 23 neutrons
44Ca 2.086% 44Ca is stable with 24 neutrons
45Ca syn 162.7 d β− 0.258 45Sc
46Ca 0.004% >2.8×1015 y β−β−  ? 46Ti
47Ca syn 4.536 d β− 0.694, 1.99 47Sc
γ 1.297 -
48Ca 0.187% >4×1019 y β−β−  ? 48Ti
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Calcium (pronounced /ˈkælsiəm/, KAL-see-əm) is the chemical element with the symbol Ca and atomic number 20. It has an atomic mass of 40.078 amu. .Calcium is a soft gray alkaline earth metal, and is the fifth most abundant element by mass in the Earth's crust.^ Natural Occurrence Titanium is the ninth most abundant element in the earth's crust.
  • Titanium (EHC 24, 1982) 9 January 2010 0:56 UTC www.inchem.org [Source type: Academic]

 ^ Sources and uses Titanium, the ninth most abundant element in the earth's crust, is widely distributed.
  • Titanium (EHC 24, 1982) 9 January 2010 0:56 UTC www.inchem.org [Source type: Academic]

 .Calcium is also the fifth most abundant dissolved ion in seawater by both molarity and mass, after sodium, chloride, magnesium, and sulfate.^ The metallic characteristics of titanium are shown in compounds such as titanium chloride, phosphate, sulfate, and nitrate, whereas the non-metallic characteristics are exhibited in a series of titanates, e.g., calcium, iron, and sodium titanates.
  • Titanium (EHC 24, 1982) 9 January 2010 0:56 UTC www.inchem.org [Source type: Academic]

 ^ PEER REVIEWED** Methods of Manufacturing: Sodium cyanide can be prepared by heating sodium amide with carbon, by melting sodium chloride and calcium cyanamide together in an electric furnace ...

 ^ Infusion of /each/ compound resulted in immediate and ipsilateral increases in the fractional excretion of sodium, potassium, calcium and magnesium.

 [1]
.Calcium is essential for living organisms, particularly in cell physiology, where movement of the calcium ion Ca2+ into and out of the cytoplasm functions as a signal for many cellular processes.^ A group of proteins that bind calcium and move it into cells.
  • Dictionary of Cancer Terms - National Cancer Institute 10 February 2010 12:52 UTC www.cancer.gov [Source type: Academic]

 ^ A protein that is made by many different types of cells and is involved in processes that take place both inside and outside of the cell.
  • Dictionary of Cancer Terms - National Cancer Institute 10 February 2010 12:52 UTC www.cancer.gov [Source type: Academic]

 ^ Describes the process inside a cell that occurs when the same signal is shared by two or more signaling pathways.
  • Dictionary of Cancer Terms - National Cancer Institute 10 February 2010 12:52 UTC www.cancer.gov [Source type: Academic]

 .As a major material used in mineralization of bones and shells, calcium is the most abundant metal by mass in many animals.^ A drug used in the treatment of hypercalcemia (abnormally high levels of calcium in the blood) and cancer that has spread to the bone (bone metastases).
  • Dictionary of Cancer Terms - National Cancer Institute 10 February 2010 12:52 UTC www.cancer.gov [Source type: Academic]

 ^ Cholecalciferol helps the body use calcium and phosphorus to make strong bones and teeth.
  • Dictionary of Cancer Terms - National Cancer Institute 10 February 2010 12:52 UTC www.cancer.gov [Source type: Academic]

Contents

Notable characteristics

Flame test. Brick red color originates from calcium.
.Chemically calcium is reactive and soft for a metal (though harder than lead, it can be cut with a knife with difficulty).^ Metal cyanides/ [Bretherick, L. Handbook of Reactive Chemical Hazards.

 .It is a silvery metallic element that must be extracted by electrolysis from a fused salt like calcium chloride.^ The metallic characteristics of titanium are shown in compounds such as titanium chloride, phosphate, sulfate, and nitrate, whereas the non-metallic characteristics are exhibited in a series of titanates, e.g., calcium, iron, and sodium titanates.
  • Titanium (EHC 24, 1982) 9 January 2010 0:56 UTC www.inchem.org [Source type: Academic]

 ^ A procedure that uses gold salts (a salt form of the metal element gold) to treat diseases, such as rheumatoid arthritis.
  • Dictionary of Cancer Terms - National Cancer Institute 10 February 2010 12:52 UTC www.cancer.gov [Source type: Academic]

 [2] .Once produced, it rapidly forms a gray-white oxide and nitride coating when exposed to air.^ A slowly progressing cancer that starts in blood-forming tissues such as the bone marrow, and causes large numbers of white blood cells to be produced and enter the blood stream.
  • Dictionary of Cancer Terms - National Cancer Institute 10 February 2010 12:52 UTC www.cancer.gov [Source type: Academic]

 ^ Titanium tetrachloride is a liquid, which is stable in dry air, but decomposes in cold water to form titanium oxide and hydrochloric acid.
  • Titanium (EHC 24, 1982) 9 January 2010 0:56 UTC www.inchem.org [Source type: Academic]

 It is somewhat difficult to ignite, unlike magnesium, but when lit, the metal burns in air with a brilliant high-intensity red light. .Calcium metal reacts with water, evolving hydrogen gas at a rate rapid enough to be noticeable, but not fast enough at room temperature to generate much heat.^ Contact with metals may evolve flammable hydrogen gas.

 ^ PEER REVIEWED** Cyanide may react with carbon dioxide in ordinary air to form toxic hydrogen cyanide gas.

 ^ The resulting cyanide ion may then form hydrogen cyanide or react with various metals present in natural water.

 .In powdered form, however, the reaction with water is extremely rapid, as the increased surface area of the powder accelerates the reaction with the water.^ Reaction with water may generate much heat which will increase the concentration of fumes in the air.

 ^ It is extremely resistant to corrosion and, in the form of a powder or dust, is highly flammable and explosive.
  • Titanium (EHC 24, 1982) 9 January 2010 0:56 UTC www.inchem.org [Source type: Academic]

 .Part of the slowness of the calcium-water reaction results from the metal being partly protected by insoluble white calcium hydroxide.^ Accidental exposure to liquid titanium tetrachloride, which was then washed off, resulted in severe burning of the skin, due to an exothermic reaction between the titanium tetrachloride and water.
  • Titanium (EHC 24, 1982) 9 January 2010 0:56 UTC www.inchem.org [Source type: Academic]

 ^ Titanium metal powder is usually produced by reaction of the metal with hydrogen; the resulting brittle titanium hydride is then crushed before heating in a vacuum to remove the hydrogen (Stamper, 1970).
  • Titanium (EHC 24, 1982) 9 January 2010 0:56 UTC www.inchem.org [Source type: Academic]

 ^ Contact with water resulted in severe burns due to the exothermic reaction between titanium tetra chloride and water.
  • Titanium (EHC 24, 1982) 9 January 2010 0:56 UTC www.inchem.org [Source type: Academic]

 .In water solutions of acids where the salt is water soluble, calcium reacts vigorously.^ In this procedure, the oxides are converted, under heating, into water-soluble sulfates by fumes of sulfuric acid, after which the corresponding sulfates are identified by staining reactions.
  • Titanium (EHC 24, 1982) 9 January 2010 0:56 UTC www.inchem.org [Source type: Academic]
Calcium, with a specific mass of 1.55 g/cm3, is the lightest of the alkali earth metals; magnesium (1.74) and beryllium (1.84) are heavier although they are lighter in atomic mass. .From strontium on, the alkali earth metals get heavier along with the atomic mass.^ Properties and analytical methods Titanium is a grey metal with an atomic number of 22 and a relative atomic mass of 47.9.
  • Titanium (EHC 24, 1982) 9 January 2010 0:56 UTC www.inchem.org [Source type: Academic]
.Calcium has a higher electrical resistivity than copper or aluminium.^ Uses of Titanium Titanium, used as a construction material, is usually in the form of alloys, most of which have higher strength than pure titanium and enhanced corrosion resistance.
  • Titanium (EHC 24, 1982) 9 January 2010 0:56 UTC www.inchem.org [Source type: Academic]

 Yet, weight for weight, allowing for its much lower density, it is a rather better conductor than either. .However, its use in terrestrial applications is usually limited by its high reactivity with air.^ Using X-ray fluorescence for the determination of titanium in air, a detection limit of 0.011 g/m 3 can be achieved; for human tissues, a detection limit of 0.3 mg/kg has been reported.
  • Titanium (EHC 24, 1982) 9 January 2010 0:56 UTC www.inchem.org [Source type: Academic]

 ^ The detection limit for titanium in air using atomic absorption spectrophotometry (AAS) is about 0.07 g/m 3 .
  • Titanium (EHC 24, 1982) 9 January 2010 0:56 UTC www.inchem.org [Source type: Academic]

 ^ For example, trace metals collected on filter paper by a high volume air sampler for 25 h were analysed by Dittrich & Cothern (1971) using the XRF technique.
  • Titanium (EHC 24, 1982) 9 January 2010 0:56 UTC www.inchem.org [Source type: Academic]
Calcium salts are colorless from any contribution of the calcium, and ionic solutions of calcium (Ca2+) are colorless as well. Many calcium salts are not soluble in water. When in solution, the calcium ion to the human taste varies remarkably, being reported as mildly salty, sour, "mineral like" or even "soothing." .It is apparent that many animals can taste, or develop a taste, for calcium, and use this sense to detect the mineral in salt licks or other sources.^ The use of drugs, vitamins, or other agents to try to reduce the risk of, or delay the development or recurrence of, cancer.
  • Dictionary of Cancer Terms - National Cancer Institute 10 February 2010 12:52 UTC www.cancer.gov [Source type: Academic]

 ^ Other titanium minerals are known which are locally abundant in some deposits, but have not been used commercially.
  • Titanium (EHC 24, 1982) 9 January 2010 0:56 UTC www.inchem.org [Source type: Academic]

 [3] In human nutrition, soluble calcium salts may be added to tart juices without much effect to the average palate.
.Calcium is the fifth most abundant element by mass in the human body, where it is a common cellular ionic messenger with many functions, and serves also as a structural element in bone.^ It is the most common mineral in the body.
  • Dictionary of Cancer Terms - National Cancer Institute 10 February 2010 12:52 UTC www.cancer.gov [Source type: Academic]

 ^ Sources and uses Titanium, the ninth most abundant element in the earth's crust, is widely distributed.
  • Titanium (EHC 24, 1982) 9 January 2010 0:56 UTC www.inchem.org [Source type: Academic]

 ^ Natural Occurrence Titanium is the ninth most abundant element in the earth's crust.
  • Titanium (EHC 24, 1982) 9 January 2010 0:56 UTC www.inchem.org [Source type: Academic]

 .It is the relatively high atomic-numbered calcium in the skeleton which causes bone to be radio-opaque.^ Properties and analytical methods Titanium is a grey metal with an atomic number of 22 and a relative atomic mass of 47.9.
  • Titanium (EHC 24, 1982) 9 January 2010 0:56 UTC www.inchem.org [Source type: Academic]

 ^ Leukemia is a cancer that starts in blood-forming tissue such as the bone marrow, and causes large numbers of abnormal blood cells to be produced and enter the blood.
  • Dictionary of Cancer Terms - National Cancer Institute 10 February 2010 12:52 UTC www.cancer.gov [Source type: Academic]

 ^ A slowly progressing cancer that starts in blood-forming tissues such as the bone marrow, and causes large numbers of white blood cells to be produced and enter the blood stream.
  • Dictionary of Cancer Terms - National Cancer Institute 10 February 2010 12:52 UTC www.cancer.gov [Source type: Academic]

 Of the human body's solid components after drying (as for example, after cremation), about a third of the total mass is the approximately one kilogram of calcium which composes the average skeleton (the remainder being mostly phosphorus and oxygen).

H and K lines

Visible spectra of many stars, including the Sun, exhibit strong absorption lines of singly-ionized calcium. Prominent among these are the H-line at 3968.5 Å and the K line at 3933.7 Å of singly-ionized calcium, or Ca II. For the Sun and stars with low temperatures, the prominence of the H and K lines can be an indication of strong magnetic activity in the chromosphere. Measurement of periodic variations of these active regions can also be used to deduce the rotation periods of these stars.[4]

Compounds

.Calcium, combined with phosphate to form hydroxylapatite, is the mineral portion of human and animal bones and teeth.^ The mineral calcium, combined with a form of the sugar glucose.
  • Dictionary of Cancer Terms - National Cancer Institute 10 February 2010 12:52 UTC www.cancer.gov [Source type: Academic]

 ^ A mineral needed for healthy teeth, bones, and other body tissues.
  • Dictionary of Cancer Terms - National Cancer Institute 10 February 2010 12:52 UTC www.cancer.gov [Source type: Academic]

 ^ Cholecalciferol helps the body use calcium and phosphorus to make strong bones and teeth.
  • Dictionary of Cancer Terms - National Cancer Institute 10 February 2010 12:52 UTC www.cancer.gov [Source type: Academic]

 The mineral portion of some corals can also be transformed into hydroxylapatite.
.Calcium hydroxide (slaked lime) is used in many chemical refinery processes and is made by heating limestone at high temperature (above 825 °C) and then carefully adding water to it.^ A chemical used to disinfect water and as a bleach.
  • Dictionary of Cancer Terms - National Cancer Institute 10 February 2010 12:52 UTC www.cancer.gov [Source type: Academic]

 ^ A protein that is made by many different types of cells and is involved in processes that take place both inside and outside of the cell.
  • Dictionary of Cancer Terms - National Cancer Institute 10 February 2010 12:52 UTC www.cancer.gov [Source type: Academic]

 ^ A type of cell that makes neurohormones (chemicals that are made by nerve cells and used to send signals to other cells) and releases them into the blood.
  • Dictionary of Cancer Terms - National Cancer Institute 10 February 2010 12:52 UTC www.cancer.gov [Source type: Academic]

 When lime is mixed with sand, it hardens into a mortar and is turned into plaster by carbon dioxide uptake. Mixed with other compounds, lime forms an important part of Portland cement.
Calcium carbonate (CaCO3) is one of the common compounds of calcium. It is heated to form quicklime (CaO), which is then added to water (H2O). .This forms another material known as slaked lime (Ca(OH)2), which is an inexpensive base material used throughout the chemical industry.^ Uses of Titanium Titanium, used as a construction material, is usually in the form of alloys, most of which have higher strength than pure titanium and enhanced corrosion resistance.
  • Titanium (EHC 24, 1982) 9 January 2010 0:56 UTC www.inchem.org [Source type: Academic]

 ^ It is also used in the chemical industry as a lining material, because of its corrosion-resistant properties.
  • Titanium (EHC 24, 1982) 9 January 2010 0:56 UTC www.inchem.org [Source type: Academic]

 ^ The remainder is used in the chemical and electrochemical processing industries, for handling some of the most corrosive processes, and in marine and ordnance applications.
  • Titanium (EHC 24, 1982) 9 January 2010 0:56 UTC www.inchem.org [Source type: Academic]

 Chalk, marble, and limestone are all forms of calcium carbonate.
.When water percolates through limestone or other soluble carbonate rocks, it partially dissolves the rock and causes cave formation and characteristic stalactites and stalagmites and also forms hard water.^ Titanium also occurs to a lesser degree in rocks such as brookite, anatase, and in feldspars, micas, biotites, and others in the form of isomorphic impurities.
  • Titanium (EHC 24, 1982) 9 January 2010 0:56 UTC www.inchem.org [Source type: Academic]

 .Other important calcium compounds are calcium nitrate, calcium sulfide, calcium chloride, calcium carbide, calcium cyanamide and calcium hypochlorite.^ Other titanium compounds, such as the hydride, carbide, and boride, may have fibrogenic properties according to experimental animal studies.
  • Titanium (EHC 24, 1982) 9 January 2010 0:56 UTC www.inchem.org [Source type: Academic]

 ^ The metallic characteristics of titanium are shown in compounds such as titanium chloride, phosphate, sulfate, and nitrate, whereas the non-metallic characteristics are exhibited in a series of titanates, e.g., calcium, iron, and sodium titanates.
  • Titanium (EHC 24, 1982) 9 January 2010 0:56 UTC www.inchem.org [Source type: Academic]

Isotopes

Main article: Isotopes of calcium
.Calcium has four stable isotopes (40Ca and 42Ca through 44Ca), plus two more isotopes (46Ca and 48Ca) that have such long half-lives that for all practical purposes they can be considered stable.^ All living things are made up of one or more cells.
  • Dictionary of Cancer Terms - National Cancer Institute 10 February 2010 12:52 UTC www.cancer.gov [Source type: Academic]

 .The 20% range in relative mass among naturally-occurring calcium isotopes is greater than for any element except hydrogen and helium.^ An elevated fibrogenic action and pronounced dystrophy of the liver, kidneys, and sometimes of the myocardium were found to occur to a greater extent with the borides than with the carbides.
  • Titanium (EHC 24, 1982) 9 January 2010 0:56 UTC www.inchem.org [Source type: Academic]

 ^ A metallic element that occurs naturally in tiny amounts in air, water, soil, and food.
  • Dictionary of Cancer Terms - National Cancer Institute 10 February 2010 12:52 UTC www.cancer.gov [Source type: Academic]

 Calcium also has a cosmogenic isotope, radioactive 41Ca, which has a half-life of 103,000 years. .Unlike cosmogenic isotopes that are produced in the atmosphere, 41Ca is produced by neutron activation of 40Ca.^ ZOLLER, W. H. & GORDON, G.E. (1970) Instrumental neutron activation analysis of atmospheric pollutants utilizing Ge(Li)-ray detectors.
  • Titanium (EHC 24, 1982) 9 January 2010 0:56 UTC www.inchem.org [Source type: Academic]

 Most of its production is in the upper metre or so of the soil column, where the cosmogenic neutron flux is still sufficiently strong. .41Ca has received much attention in stellar studies because it decays to 41K, a critical indicator of solar-system anomalies.^ FloraCraft and HYGLOSS solar system and DNA educational kits for children, made in both the U.S. and in China, because surface paints on the kit\'s wires have excessive lead.
  • Lead Paint Toy Recalls - Latest Lead Toy Recalls - Toxic Childrens Products - thedailygreen.com 14 January 2010 19:52 UTC www.thedailygreen.com [Source type: General]

 ^ Compared with a simultaneously studied group (group 1) of rats receiving identical gentamicin dosages and normal diets, Ca++ supplementation ameliorated gentamicin-induced acute renal failure.

 ^ The treatment enabled him to stimulate his physical stamina, or immune system, so much that his tuberculosis went into remission and he was able to complete his studies.
.97% of naturally occurring calcium is in the form of 40Ca.^ These types of foods have been shown to contain not only minerals in natural food forms, but also important protein chaperones such as ATX1 and ceruplasmin [39,40].
  • Calcium 10 February 2010 12:52 UTC goldrust.net [Source type: FILTERED WITH BAYES]

 ^ However, there are concerns that the natural forms of calcium supplements may contain significant amounts of lead.
  • Calcium | ThirdAge Articles 10 February 2010 12:52 UTC www.thirdage.com [Source type: Academic]

 ^ Ionic calcium (Ca++) is the only physiologically active form of this element.
  • Calcium 10 February 2010 12:52 UTC goldrust.net [Source type: FILTERED WITH BAYES]

 40Ca is one of the daughter products of 40K decay, along with 40Ar. While K-Ar dating has been used extensively in the geological sciences, the prevalence of 40Ca in nature has impeded its use in dating. .Techniques using mass spectrometry and a double spike isotope dilution have been used for K-Ca age dating.^ Gives techniques used and at what age.
  • Information Resources for Livestock and Poultry Handling and Transport 19 January 2010 9:53 UTC www.nal.usda.gov [Source type: Academic]
The most abundant isotope, 40Ca, has a nucleus of 20 protons and 20 neutrons. .This is the heaviest stable isotope of any element which has equal numbers of protons and neutrons.^ The concentration and distribution, in healthy human tissues, of a large number of stable elements including titanium was studied by Hamilton et al.
  • Titanium (EHC 24, 1982) 9 January 2010 0:56 UTC www.inchem.org [Source type: Academic]

 .In supernova explosions, calcium is formed from the reaction of carbon with various numbers of alpha particles (helium nuclei), until the most common calcium isotope (containing 10 helium nuclei) has been synthesized.^ The most common titanium minerals are ilmenite (TiFeO 3 ), which can contain a maximum concentration of titanium dioxide (TiO 2 ) of 530 g/kg, and rutile, which is 100% titanium dioxide.
  • Titanium (EHC 24, 1982) 9 January 2010 0:56 UTC www.inchem.org [Source type: Academic]

 ^ Its most common oxidation state is +4 (titanic compounds), but +3 (titanous compounds) and +2 forms are also known, in addition to oxy forms such as titanyl chloride (TiOCl 2 ).
  • Titanium (EHC 24, 1982) 9 January 2010 0:56 UTC www.inchem.org [Source type: Academic]

 [citation needed]

Isotope fractionation

As with the isotopes of other elements, a variety of processes fractionate, or alter the relative abundance of, calcium isotopes.[5] The best studied of these processes is the mass dependent fractionation of calcium isotopes that accompanies the precipitation of calcium minerals, such as calcite, aragonite and apatite, from solution. Isotopically light calcium is preferentially incorporated into minerals, leaving the solution from which the mineral precipitated enriched in isotopically heavy calcium. At room temperature the magnitude of this fractionation is roughly 0.25‰ (0.025%) per atomic mass unit (AMU). Mass-dependant differences in calcium isotope composition conventionally are expressed the ratio of two isotopes (usually 44Ca/40Ca) in a sample compared to the same ratio in a standard reference material. 44Ca/40Ca varies by about 1% among common earth materials.[6]
Calcium isotope fractionation during mineral formation has led to several applications of calcium isotopes. In particular, the 1997 observation by Skulan and DePaolo[7] that calcium minerals are isotopically lighter than the solutions from which the minerals precipitate is the basis of analogous applications in medicine and in paleooceanography. .In animals with skeletons mineralized with calcium the calcium isotopic composition of soft tissues reflects the relative rate of formation and dissolution of skeletal mineral.^ A condition in which abnormal amounts of calcium salts are found in soft tissue, such as muscle.
  • Dictionary of Cancer Terms - National Cancer Institute 10 February 2010 12:52 UTC www.cancer.gov [Source type: Academic]

 ^ It is used as a drug to increase calcium levels in the body in order to treat skeletal and tissue-related calcium deficiencies caused by kidney or thyroid disorders.
  • Dictionary of Cancer Terms - National Cancer Institute 10 February 2010 12:52 UTC www.cancer.gov [Source type: Academic]

 In humans changes in the calcium isotopic composition of urine have been shown to be related to changes in bone mineral balance. .When the rate of bone formation exceeds the rate of bone resorption, soft tissue 44Ca/40Ca rises.^ A soft tissue tumor that begins in a tendon (tough, fibrous, cord-like tissue that connects muscle to bone or to another structure).
  • Dictionary of Cancer Terms - National Cancer Institute 10 February 2010 12:52 UTC www.cancer.gov [Source type: Academic]

 ^ Clear cell sarcoma can spread from the kidney to other organs, most commonly the bone, but also including the lungs, brain, and soft tissues of the body.
  • Dictionary of Cancer Terms - National Cancer Institute 10 February 2010 12:52 UTC www.cancer.gov [Source type: Academic]

 .Soft tissue 44Ca/40Ca falls when bone resorption exceeds bone formation.^ The tolerance of soft tissue and bone to contact with titanium was illustrated by lack of irritation, normality of wound-healing and the encapsulation of the metal by fibrous tissue.
  • Titanium (EHC 24, 1982) 9 January 2010 0:56 UTC www.inchem.org [Source type: Academic]

 .Because of this relationship, calcium isotopic measurements of urine or blood may be useful in the early detection of metabolic bone diseases like osteoporosis.^ A slowly progressing disease in which too many white blood cells (not lymphocytes) are made in the bone marrow.
  • Dictionary of Cancer Terms - National Cancer Institute 10 February 2010 12:52 UTC www.cancer.gov [Source type: Academic]

 ^ Too much cholesterol in the blood may build up in blood vessel walls, block blood flow to tissues and organs, and increase the risk of developing heart disease and stroke.
  • Dictionary of Cancer Terms - National Cancer Institute 10 February 2010 12:52 UTC www.cancer.gov [Source type: Academic]

 ^ A drug used in the treatment of metabolic acidosis (a disorder in which the blood is too acidic).
  • Dictionary of Cancer Terms - National Cancer Institute 10 February 2010 12:52 UTC www.cancer.gov [Source type: Academic]

 [8]
.A similar system exists in the ocean, where seawater 44Ca/40Ca tends to rise when the rate of removal of Ca2+ from seawater by mineral precipitation exceeds the input of new calcium into the ocean, and fall when calcium input exceeds mineral precipitation.^ In solution, (NH 4 ) 2 SO 4 and (NH 4 ) 2 C 2 O 4 will remove Ca and Ba as a precipitate.
  • Mineral Species sorted by the element Mg Magnesium 16 January 2010 3:03 UTC webmineral.com [Source type: Reference]

 It follows that rising 44Ca/40Ca corresponds to falling seawater Ca2+ concentration, and falling 44Ca/40Ca corresponds to rising seawater Ca2+ concentration. In 1997 Skulan and DePaolo presented the first evidence of change in seawater 44Ca/40Ca over geologic time, along with a theoretical explanation of these changes. More recent papers have confirmed this observation, demonstrating that seawater Ca2+ concentration is not constant, and that the ocean probably never is in “steady state” with respect to its calcium input and output.[9] [10]This has important climatological implications, as the marine calcium cycle is closely tied to the carbon cycle (see below).

Geochemical cycling

Calcium provides an important link between tectonics, climate and the carbon cycle. .In the simplest terms, uplift of mountains exposes Ca-bearing rocks to chemical weathering and releases Ca2+ into surface water.^ A type of cell that makes neurohormones (chemicals that are made by nerve cells and used to send signals to other cells) and releases them into the blood.
  • Dictionary of Cancer Terms - National Cancer Institute 10 February 2010 12:52 UTC www.cancer.gov [Source type: Academic]

 ^ CA 19-9 is a tumor marker released into the bloodstream from both cancer cells and normal cells.
  • Dictionary of Cancer Terms - National Cancer Institute 10 February 2010 12:52 UTC www.cancer.gov [Source type: Academic]

 This Ca2+ eventually is transported to the ocean where it reacts with dissolved CO2 to form limestone. Some of this limestone settles to the sea floor where it is incorporated into new rocks. Dissolved CO2, along with carbonate and bicarbonate ions, are referred to as dissolved inorganic carbon (DIC).
The actual reaction is more complicated and involves the bicarbonate ion (HCO3-) that forms when CO2 reacts with water at seawater pH:
Ca2+ + 2HCO3 → CaCO3 (limestone) + CO2 + H2O
.Note that at ocean pH most of the CO2 produced in this reaction is immediately converted back into HCO3-.^ In this procedure, the oxides are converted, under heating, into water-soluble sulfates by fumes of sulfuric acid, after which the corresponding sulfates are identified by staining reactions.
  • Titanium (EHC 24, 1982) 9 January 2010 0:56 UTC www.inchem.org [Source type: Academic]

 .The reaction results in a net transport of one molecule of CO2 from the ocean/atmosphere into the lithosphere.^ The combustion of coal and oil results in a discharge of trace amounts of several elements, including titanium, into the atmosphere.
  • Titanium (EHC 24, 1982) 9 January 2010 0:56 UTC www.inchem.org [Source type: Academic]

 [11]

The result is that each Ca2+ ion released by chemical weathering ultimately removes one CO2 molecule from the surficial system (atmosphere, ocean, soils and living organisms), storing it in carbonate rocks where it is likely to stay for hundreds of millions of years. The weathering of calcium from rocks thus scrubs CO2 from the ocean and atmosphere, thereby exerting a strong long-term effect on climate.[12] Analogous cycles involving magnesium, and to a much smaller extent strontium and barium, have the same effect.
As the weathering of limestone (CaCO3) liberates equimolar amounts of Ca2+ and CO2, it has no net effect on the CO2 content of the atmosphere and ocean. The weathering of silicate rocks like granite, on the other hand, is a net CO2 sink because it produces abundant Ca2+ very little CO2.

History

Calcium (Latin word calcis meaning "lime") was known as early as the first century when the Ancient Romans prepared lime as calcium oxide. .Literature dating back to 975 AD notes that plaster of paris (calcium sulphate), is useful for setting broken bones.^ A drug used in the treatment of hypercalcemia (abnormally high levels of calcium in the blood) and cancer that has spread to the bone (bone metastases).
  • Dictionary of Cancer Terms - National Cancer Institute 10 February 2010 12:52 UTC www.cancer.gov [Source type: Academic]

 ^ Cholecalciferol helps the body use calcium and phosphorus to make strong bones and teeth.
  • Dictionary of Cancer Terms - National Cancer Institute 10 February 2010 12:52 UTC www.cancer.gov [Source type: Academic]

 .It was not isolated until 1808 in England when Sir Humphry Davy electrolyzed a mixture of lime and mercuric oxide.^ Isolated by Sir Humphry Davy at the Royal Institution, London, UK. .
  • Mineral Species sorted by the element Na Sodium 6 January 2010 8:54 UTC webmineral.com [Source type: FILTERED WITH BAYES]

 Davy was trying to isolate calcium; when he heard that Swedish chemist Jöns Jakob Berzelius and Pontin prepared calcium amalgam by electrolyzing lime in mercury, he tried it himself. He worked with electrolysis throughout his life and also discovered/isolated sodium, potassium, magnesium, boron and barium. .Calcium metal was not available in large scale until the beginning of the 20th century.^ The first large-scale industrial application of titanium was in the aluminium anodizing industry, where the metal supporting racks were made almost exclusively of titanium.
  • Titanium (EHC 24, 1982) 9 January 2010 0:56 UTC www.inchem.org [Source type: Academic]

Occurrence

.Calcium is not naturally found in its elemental state.^ Environmental levels and exposures Owing to its great affinity for oxygen and other elements, titanium does not exist in the metallic state in nature.
  • Titanium (EHC 24, 1982) 9 January 2010 0:56 UTC www.inchem.org [Source type: Academic]

 ^ Owing to its great affinity for oxygen and other elements, titanium does not exist in the metallic state in nature.
  • Titanium (EHC 24, 1982) 9 January 2010 0:56 UTC www.inchem.org [Source type: Academic]

 ^ Calcium minerals, in their elemental state, are normally only 8 to 40% biologically available to animals and humans.
  • Calcium 10 February 2010 12:52 UTC goldrust.net [Source type: FILTERED WITH BAYES]

 Calcium occurs most commonly in sedimentary rocks in the minerals calcite, dolomite and gypsum. .It also occurs in igneous and metamorphic rocks chiefly in the silicate minerals: plagioclase, amphiboles, pyroxenes and garnets.^ Rutile, ilmenite, brookite, and other common titanium minerals accumulate in sedimentary rocks and sometimes in certain soils as the end products of metamorphism of titanium-containing minerals and rocks.
  • Titanium (EHC 24, 1982) 9 January 2010 0:56 UTC www.inchem.org [Source type: Academic]
See also: Category:Calcium minerals

Applications

Calcium is used[13]

Calcium compounds

.
  • Calcium carbonate (CaCO3) is used in manufacturing cement and mortar, lime, limestone (usually used in the steel industry) and aids in production in the glass industry.^ In addition, titanium dioxide is used in ceramic capacitors and electromechanical transducers, welding-rod coatings, and in the production of glass fibres.
    • Titanium (EHC 24, 1982) 9 January 2010 0:56 UTC www.inchem.org [Source type: Academic]

     ^ Similar anodes are used in cathodic protection systems of ships, harbour installations, water heaters, and cleaning lines in the production of stainless steel strip.
    • Titanium (EHC 24, 1982) 9 January 2010 0:56 UTC www.inchem.org [Source type: Academic]

     ^ Metallic titanium is mainly used in the aircraft industry and in the production of high-strength, corrosion-resistant alloys.
    • Titanium (EHC 24, 1982) 9 January 2010 0:56 UTC www.inchem.org [Source type: Academic]

     .It also has chemical and optical uses as mineral specimens in toothpastes, for example.
  • Calcium hydroxide solution (Ca(OH)2) (also known as limewater) is used to detect the presence of carbon dioxide by being bubbled through a solution.^ Titanium dioxide, salicylate, oxide, and tannate have been used in various dermatological and cosmetic formulations, without any known adverse effects.
    • Titanium (EHC 24, 1982) 9 January 2010 0:56 UTC www.inchem.org [Source type: Academic]

     ^ Other titanium minerals are known which are locally abundant in some deposits, but have not been used commercially.
    • Titanium (EHC 24, 1982) 9 January 2010 0:56 UTC www.inchem.org [Source type: Academic]

     .It turns cloudy where CO2 is present.
  • Calcium arsenate (Ca3(AsO4)2) is used in insecticides.
  • Calcium carbide (CaC2) is used to make acetylene gas (for use in acetylene torches for welding) and in the manufacturing of plastics.
  • Calcium chloride (CaCl2) is used in ice removal and dust control on dirt roads, in conditioner for concrete, as an additive in canned tomatoes, and to provide body for automobile tires.
  • Calcium cyclamate (Ca(C6H11NHSO3)2) was used as a sweetening agent but is no longer permitted for use because of suspected cancer-causing properties.
  • Calcium gluconate (Ca(C6H11O7)2) is used as a food additive and in vitamin pills.
  • Calcium hypochlorite (Ca(OCl)2) is used as a swimming pool disinfectant, as a bleaching agent, as an ingredient in deodorant, and in algaecide and fungicide.
  • Calcium permanganate (Ca(MnO4)2) is used in liquid rocket propellant, textile production, as a water sterilizing agent and in dental procedures.
  • Calcium phosphate (Ca3(PO4)2) is used as a supplement for animal feed, fertilizer, in commercial production for dough and yeast products, in the manufacture of glass, and in dental products.
  • Calcium phosphide (Ca3P2) is used in fireworks, rodenticide, torpedoes and flares.
  • Calcium stearate (Ca(C18H35O2)2) is used in the manufacture of wax crayons, cements, certain kinds of plastics and cosmetics, as a food additive, in the production of water resistant materials and in the production of paints.
  • Calcium sulfate (CaSO4·2H2O) is used as common blackboard chalk, as well as, in its hemihydrate form better known as Plaster of Paris.
  • Calcium tungstate (CaWO4) is used in luminous paints, fluorescent lights and in X-ray studies.
  • Hydroxylapatite (Ca5(PO4)3(OH), but is usually written Ca10(PO4)6(OH)2) makes up seventy percent of bone.^ Liquid Calcium Plus Vitamin D3, 600mg, 100 Softgels from All Nature .
    • Coral Calcium/Calcium Supplement/Calcium Citrate/Liquid Calcium, Highly Absorbable Dietary Supplement! 10 February 2010 12:52 UTC www.ihealthtree.com [Source type: Academic]

     ^ We offer extensive experience in all types of rubber & will assist you in product design as well as material selection & specification.
    • Rubber Molding Information and Resources 30 January 2010 3:18 UTC www.rubbermolding.org [Source type: Reference]

     ^ Na 3H3(Mn++,Ca,Fe)TiSi6(O,OH)18•2(H2O) .
    • Mineral Species sorted by the element Na Sodium 6 January 2010 8:54 UTC webmineral.com [Source type: FILTERED WITH BAYES]

     Also carbonated-calcium deficient hydroxylapatite is the main mineral of which dental enamel and dentin are comprised.

Nutrition

Main articles: Calcium in biology and Calcium metabolism
Recommended adequate intake by the IOM for calcium:[14]
Age Calcium (mg/day)
0–6 months 210
7–12 months 270
1–3 years 500
4–8 years 800
9–18 years 1300
19–50 years 1000
51+ years 1200
Calcium is an important component of a healthy diet and a mineral necessary for life. The National Osteoporosis Foundation says, "Calcium plays an important role in building stronger, denser bones early in life and keeping bones strong and healthy later in life." Approximately ninety-nine percent of the body's calcium is stored in the bones and teeth.[15] .The rest of the calcium in the body has other important uses, such as some exocytosis, especially neurotransmitter release, and muscle contraction.^ Other titanium minerals are known which are locally abundant in some deposits, but have not been used commercially.
  • Titanium (EHC 24, 1982) 9 January 2010 0:56 UTC www.inchem.org [Source type: Academic]

 In the electrical conduction system of the heart, calcium replaces sodium as the mineral that depolarizes the cell, proliferating the action potential. In cardiac muscle, sodium influx commences an action potential, but during potassium efflux, the cardiac myocyte experiences calcium influx, prolonging the action potential and creating a plateau phase of dynamic equilibrium. .Long-term calcium deficiency can lead to rickets and poor blood clotting and in case of a menopausal woman, it can lead to osteoporosis, in which the bone deteriorates and there is an increased risk of fractures.^ It may decrease pain, the risk of fractures, and the development of new bone metastases.
  • Dictionary of Cancer Terms - National Cancer Institute 10 February 2010 12:52 UTC www.cancer.gov [Source type: Academic]

 ^ Infants with the disorder get infections caused by bacteria, and are at an increased risk of acute myelogenous leukemia (AML) or myelodysplasia (a bone marrow disorder).
  • Dictionary of Cancer Terms - National Cancer Institute 10 February 2010 12:52 UTC www.cancer.gov [Source type: Academic]

 ^ Too much cholesterol in the blood may build up in blood vessel walls, block blood flow to tissues and organs, and increase the risk of developing heart disease and stroke.
  • Dictionary of Cancer Terms - National Cancer Institute 10 February 2010 12:52 UTC www.cancer.gov [Source type: Academic]

 .While a lifelong deficit can affect bone and tooth formation, over-retention can cause hypercalcemia (elevated levels of calcium in the blood), impaired kidney function and decreased absorption of other minerals.^ A rare cancer that forms in the outer layer of tissue of the adrenal gland (a small organ on top of each kidney that makes steroid hormones, adrenaline, and noradrenaline to control heart rate, blood pressure, and other body functions).
  • Dictionary of Cancer Terms - National Cancer Institute 10 February 2010 12:52 UTC www.cancer.gov [Source type: Academic]

 ^ C cells make calcitonin, a hormone that helps control the calcium level in the blood.
  • Dictionary of Cancer Terms - National Cancer Institute 10 February 2010 12:52 UTC www.cancer.gov [Source type: Academic]

 ^ Creatinine levels are measured to monitor kidney function.
  • Dictionary of Cancer Terms - National Cancer Institute 10 February 2010 12:52 UTC www.cancer.gov [Source type: Academic]

 [16] High calcium intakes or high calcium absorption were previously thought to contribute to the development of kidney stones. .However, a high calcium intake has been associated with a lower risk for kidney stones in more recent research.^ When the calcium level is too high, calcitonin lowers it.
  • Dictionary of Cancer Terms - National Cancer Institute 10 February 2010 12:52 UTC www.cancer.gov [Source type: Academic]

 [17][18][19] .Vitamin D is needed to absorb calcium.^ Calcipotriene (Dovonex) interacts with CALCIUM Calcipotriene (Dovonex) is a drug that is similar to vitamin D. Vitamin D helps your body absorb calcium.
  • CALCIUM: Uses, Side Effects, Interactions and Warnings - WebMD 10 February 2010 12:52 UTC www.webmd.com [Source type: Academic]
Dairy products, such as milk and cheese, are a well-known source of calcium. .Some individuals are allergic to dairy products and even more people, particularly those of non Indo-European descent, are lactose-intolerant, leaving them unable to consume non-fermented dairy products in quantities larger than about half a liter per serving.^ A substance made in the muscle and liver tissue and found in certain foods, such as meat, poultry, fish, and some dairy products.
  • Dictionary of Cancer Terms - National Cancer Institute 10 February 2010 12:52 UTC www.cancer.gov [Source type: Academic]

 ^ A form of carnitine, which is a substance made in muscle and liver tissue and found in certain foods, such as meat, poultry, fish, and some dairy products.
  • Dictionary of Cancer Terms - National Cancer Institute 10 February 2010 12:52 UTC www.cancer.gov [Source type: Academic]

 ^ The occurrence of a larger-than-expected number of cases of cancer within a group of people in a geographic area over a period of time.
  • Dictionary of Cancer Terms - National Cancer Institute 10 February 2010 12:52 UTC www.cancer.gov [Source type: Academic]

 .Others, such as vegans, avoid dairy products for ethical and health reasons.^ A form of carnitine, which is a substance made in muscle and liver tissue and found in certain foods, such as meat, poultry, fish, and some dairy products.
  • Dictionary of Cancer Terms - National Cancer Institute 10 February 2010 12:52 UTC www.cancer.gov [Source type: Academic]

 ^ A substance made in the muscle and liver tissue and found in certain foods, such as meat, poultry, fish, and some dairy products.
  • Dictionary of Cancer Terms - National Cancer Institute 10 February 2010 12:52 UTC www.cancer.gov [Source type: Academic]

 ^ Cholesterol also comes from eating foods taken from animals such as egg yolks, meat, and whole-milk dairy products.
  • Dictionary of Cancer Terms - National Cancer Institute 10 February 2010 12:52 UTC www.cancer.gov [Source type: Academic]

 Fortunately, many good sources of calcium exist. .These include seaweeds such as kelp, wakame and hijiki; nuts and seeds (like almonds and sesame); blackstrap molasses; beans; oranges; figs; quinoa; amaranth; collard greens; okra; rutabaga; broccoli; dandelion leaves; kale; and fortified products such as orange juice and soy milk.^ A member of the family of vegetables that includes broccoli, Brussels sprouts, cabbage, cauliflower, collard greens, kale, and turnips.
  • Dictionary of Cancer Terms - National Cancer Institute 10 February 2010 12:52 UTC www.cancer.gov [Source type: Academic]

 ^ Cholesterol also comes from eating foods taken from animals such as egg yolks, meat, and whole-milk dairy products.
  • Dictionary of Cancer Terms - National Cancer Institute 10 February 2010 12:52 UTC www.cancer.gov [Source type: Academic]

 .Research has found an association between diets high in animal protein and increased urinary calcium loss from the bones.^ A drug used in the treatment of hypercalcemia (abnormally high levels of calcium in the blood) and cancer that has spread to the bone (bone metastases).
  • Dictionary of Cancer Terms - National Cancer Institute 10 February 2010 12:52 UTC www.cancer.gov [Source type: Academic]

 [20][21][22] .A diet high in fruit, vegetables and cereals was demonstrated to result in greater femoral bone mineral density in older men, in comparison to a range of other diets.^ A mineral needed for healthy teeth, bones, and other body tissues.
  • Dictionary of Cancer Terms - National Cancer Institute 10 February 2010 12:52 UTC www.cancer.gov [Source type: Academic]

 Diets high in candy were found to result in lower bone density in both men and women.[23]. .An overlooked source of calcium is eggshell, which can be ground into a powder and mixed into food or a glass of water.^ Calcium Carbonate Powder 12 oz from NOW Foods .
  • Coral Calcium/Calcium Supplement/Calcium Citrate/Liquid Calcium, Highly Absorbable Dietary Supplement! 10 February 2010 12:52 UTC www.ihealthtree.com [Source type: Academic]

 ^ Calcium Lactate Powder 9 oz from NOW Foods, Discontinued .
  • Coral Calcium/Calcium Supplement/Calcium Citrate/Liquid Calcium, Highly Absorbable Dietary Supplement! 10 February 2010 12:52 UTC www.ihealthtree.com [Source type: Academic]

 ^ Calcium Gluconate Powder 7 oz from NOW Foods, Discontinued .
  • Coral Calcium/Calcium Supplement/Calcium Citrate/Liquid Calcium, Highly Absorbable Dietary Supplement! 10 February 2010 12:52 UTC www.ihealthtree.com [Source type: Academic]

 [24][25][26] Cultivated vegetables generally have less calcium than wild plants.[27]
The calcium content of most foods can be found in the USDA National Nutrient Database.[28]

Dietary calcium supplements

500 milligram calcium supplements made from calcium carbonate
Calcium supplements are used to prevent and to treat calcium deficiencies. Most experts recommend that supplements be taken with food and that no more than 600 mg should be taken at a time because the percent of calcium absorbed decreases as the amount of calcium in the supplement increases.[14] It is recommended to spread doses throughout the day. .Recommended daily calcium intake for adults ranges from 1000 to 1500 mg.^ A typical diet may contribute some 300-400 g/day, but higher intakes ranging up to 2 mg per day have been reported.
  • Titanium (EHC 24, 1982) 9 January 2010 0:56 UTC www.inchem.org [Source type: Academic]

 .It is recommended to take supplements with food to aid in absorption.^ In cancer prevention, a clinical trial that studies whether taking certain medicines, vitamins, minerals, or food supplements can prevent cancer.
  • Dictionary of Cancer Terms - National Cancer Institute 10 February 2010 12:52 UTC www.cancer.gov [Source type: Academic]
Vitamin D is added to some calcium supplements. .Proper vitamin D status is important because vitamin D is converted to a hormone in the body which then induces the synthesis of intestinal proteins responsible for calcium absorption.^ Cholesterol is important for good health and is needed for making cell walls, tissues, hormones, vitamin D, and bile acid.
  • Dictionary of Cancer Terms - National Cancer Institute 10 February 2010 12:52 UTC www.cancer.gov [Source type: Academic]

 [29]
.
  • The absorption of calcium from most food and commonly-used dietary supplements is very similar.^ Coral Calcium/Calcium Supplement/Calcium Citrate/Liquid Calcium, Highly Absorbable Dietary Supplement!
    • Coral Calcium/Calcium Supplement/Calcium Citrate/Liquid Calcium, Highly Absorbable Dietary Supplement! 10 February 2010 12:52 UTC www.ihealthtree.com [Source type: Academic]

     [30] .This is contrary to what many calcium supplement manufacturers claim in their promotional materials.
  • Milk is an excellent source of dietary calcium because it has a high concentration of calcium and the calcium in milk is excellently absorbed.^ High concentrations of titanium in food, especially cheese, can arise from the use of titanium dioxide as a whitener in the manufacture of mozzarella cheese (Kosikowski & Brown, 1969; Leone, 1973).
    • Titanium (EHC 24, 1982) 9 January 2010 0:56 UTC www.inchem.org [Source type: Academic]

     ^ Skurko & Brahnova (1973) reported high concentrations of titanium dust in the breathing zone of workers employed in the manufacture of titanium hydride.
    • Titanium (EHC 24, 1982) 9 January 2010 0:56 UTC www.inchem.org [Source type: Academic]

     [30]
  • Calcium carbonate is the most common and least expensive calcium supplement. It should be taken with food. It depends on low pH levels for proper absorption in the intestine.[31] Some studies suggests that the absorption of calcium from calcium carbonate is similar to the absorption of calcium from milk.[32][33] While most people digest calcium carbonate very well, some might develop gastrointestinal discomfort or gas. Taking magnesium with it can help to avoid constipation. .Calcium carbonate is 40% elemental calcium.^ So Calcium carbonate is 40% calcium.
    • Calcium 10 February 2010 12:52 UTC goldrust.net [Source type: FILTERED WITH BAYES]

     ^ For example, calcium carbonate provides 40% elemental calcium with only 10% of that ionized, while calcium gluconate supplies 9% elemental calcium with only 10% of that ionized.
    • Calcium 10 February 2010 12:52 UTC goldrust.net [Source type: FILTERED WITH BAYES]

     ^ For preventing high blood pressure during pregnancy (pre-eclampsia): 1-2 grams elemental calcium daily as calcium carbonate.
    • CALCIUM: Uses, Side Effects, Interactions and Warnings - WebMD 10 February 2010 12:52 UTC www.webmd.com [Source type: Academic]

     1000 mg will provide 400 mg of calcium. However, supplement labels will usually indicate how much calcium is present in each serving, not how much calcium carbonate is present.
  • Antacids, such as Tums, frequently contain calcium carbonate, and are a very commonly-used, inexpensive calcium supplement.
  • Coral Calcium is a salt of calcium derived from fossilized coral reefs. .Coral calcium is composed of calcium carbonate and trace minerals.
  • Calcium citrate can be taken without food and is the supplement of choice for individuals with achlorhydria or who are taking histamine-2 blockers or proton-pump inhibitors.^ A mineral taken primarily as a supplement to prevent osteoporosis.
    • Dictionary of Cancer Terms - National Cancer Institute 10 February 2010 12:52 UTC www.cancer.gov [Source type: Academic]

     ^ Calcium Carbonate Powder 12 oz from NOW Foods .
    • Coral Calcium/Calcium Supplement/Calcium Citrate/Liquid Calcium, Highly Absorbable Dietary Supplement! 10 February 2010 12:52 UTC www.ihealthtree.com [Source type: Academic]

     ^ In cancer prevention, a clinical trial that studies whether taking certain medicines, vitamins, minerals, or food supplements can prevent cancer.
    • Dictionary of Cancer Terms - National Cancer Institute 10 February 2010 12:52 UTC www.cancer.gov [Source type: Academic]

     [34] It is more easily digested and absorbed than calcium carbonate if taken on empty stomach and less likely to cause constipation and gas than calcium carbonate. .It also has a lower risk of contributing to the formation of kidney stones.^ The resultant adverse clinical consequences are possibly increased bone demineralization and increased risk of calcium-containing kidney stones.
    • Dietary Reference Intakes for Water, Potassium, Sodium, Chloride, and Sulfate 13 January 2010 21:34 UTC www.nap.edu [Source type: Academic]

     ^ Nutrient intake and use of beverages and the risk of kidney stones among male smokers.
    • Dietary Reference Intakes for Water, Potassium, Sodium, Chloride, and Sulfate 13 January 2010 21:34 UTC www.nap.edu [Source type: Academic]

     ^ A prospective study of dietary calcium and other nutrients and the risk of symptomatic kidney stones.
    • Calcium | ThirdAge Articles 10 February 2010 12:52 UTC www.thirdage.com [Source type: Academic]

     Calcium citrate is about 21% elemental calcium. 1000 mg will provide 210 mg of calcium. .It is more expensive than calcium carbonate and more of it must be taken to get the same amount of calcium.
  • Calcium phosphate costs more than calcium carbonate, but less than calcium citrate.^ Cancer cells take up more carbon-11 choline than normal cells, so the pictures can be used to find cancer cells in the body.
    • Dictionary of Cancer Terms - National Cancer Institute 10 February 2010 12:52 UTC www.cancer.gov [Source type: Academic]

     .It is easily absorbed and is less likely to cause constipation and gas than either.
  • Calcium lactate has similar absorption as calcium carbonate[35], but is more expensive.^ Outside occupational settings, the amount of titanium absorbed via the lungs is of little significance in relation to the intake from food, and the intake by inhalation is less than 1% of the total intake.
    • Titanium (EHC 24, 1982) 9 January 2010 0:56 UTC www.inchem.org [Source type: Academic]

     Calcium lactate and calcium gluconate are less concentrated forms of calcium and are not practical oral supplements.[34]
    • .
  • Calcium chelates are synthetic calcium compounds, with calcium bound to an organic molecule, such as malate, aspartate, or fumarate.^ In addition, there are complex organic compounds of titanium such as titanocene.
    • Titanium (EHC 24, 1982) 9 January 2010 0:56 UTC www.inchem.org [Source type: Academic]

     ^ The metallic characteristics of titanium are shown in compounds such as titanium chloride, phosphate, sulfate, and nitrate, whereas the non-metallic characteristics are exhibited in a series of titanates, e.g., calcium, iron, and sodium titanates.
    • Titanium (EHC 24, 1982) 9 January 2010 0:56 UTC www.inchem.org [Source type: Academic]

     .These forms of calcium may be better absorbed on an empty stomach.^ A form of the anticancer drug camptothecin that may have fewer side effects and work better than camptothecin.
    • Dictionary of Cancer Terms - National Cancer Institute 10 February 2010 12:52 UTC www.cancer.gov [Source type: Academic]

     ^ A form of the anticancer drug paclitaxel combined with a protein called poliglumex that may have fewer side effects and work better than paclitaxel.
    • Dictionary of Cancer Terms - National Cancer Institute 10 February 2010 12:52 UTC www.cancer.gov [Source type: Academic]

     .However, in general they are absorbed similarly to calcium carbonate and other common calcium supplements when taken with food.^ Calcium Carbonate Powder 12 oz from NOW Foods .
    • Coral Calcium/Calcium Supplement/Calcium Citrate/Liquid Calcium, Highly Absorbable Dietary Supplement! 10 February 2010 12:52 UTC www.ihealthtree.com [Source type: Academic]

     [36] The 'chelate' mimics the action that natural food performs by keeping the calcium soluble in the intestine. Thus, on an empty stomach, in some individuals, chelates might theoretically be absorbed better.
  • Microcrystalline hydroxyapatite (MH) is marketed as a calcium supplement, and has in some randomized trials been found to be more effective than calcium carbonate.
  • Orange juice with calcium added is a good dietary source for persons who have lactose intolerance.
.In July 2006, a report citing research from Fred Hutchinson Cancer Research Center in Seattle, Washington claimed that women in their 50s gained 5 pounds less in a period of 10 years by taking more than 500 mg of calcium supplements than those who did not.^ A company hired by another company or research center to take over certain parts of running a clinical trial.
  • Dictionary of Cancer Terms - National Cancer Institute 10 February 2010 12:52 UTC www.cancer.gov [Source type: Academic]

 ^ A research study that compares a particular outcome (such as lung cancer) in groups of individuals who are alike in many ways but differ by a certain characteristic (for example, female nurses who smoke compared with those who do not smoke).
  • Dictionary of Cancer Terms - National Cancer Institute 10 February 2010 12:52 UTC www.cancer.gov [Source type: Academic]

 ^ Cancer cells take up more C-11 choline than normal cells, so the pictures can be used to find cancer cells in the body.
  • Dictionary of Cancer Terms - National Cancer Institute 10 February 2010 12:52 UTC www.cancer.gov [Source type: Academic]

 However, the doctor in charge of the study, Dr. Alejandro J. Gonzalez also noted it would be "going out on a limb" to suggest calcium supplements as a weight-limiting aid.[37]

Prevention of fractures due to osteoporosis

.Such studies often do not test calcium alone, but rather combinations of calcium and vitamin D. Randomized controlled trials found both positive[38][39] and negative[40][41][42][43] effects.^ In cancer prevention, a clinical trial that studies whether taking certain medicines, vitamins, minerals, or food supplements can prevent cancer.
  • Dictionary of Cancer Terms - National Cancer Institute 10 February 2010 12:52 UTC www.cancer.gov [Source type: Academic]

 .The different results may be explained by doses of calcium and underlying rates of calcium supplementation in the control groups.^ This may happen because of a mutation (genetic change) that occurs during development, or as a result of a transplant of cells, organs, or tissues from another person or from a different species.
  • Dictionary of Cancer Terms - National Cancer Institute 10 February 2010 12:52 UTC www.cancer.gov [Source type: Academic]

 [44] .However, it is clear that increasing the intake of calcium promotes deposition of calcium in the bones, where it is of more benefit in preventing the compression fractures resulting from the osteoporotic thinning of the dendritic web of the bodies of the vertebrae, than it is at preventing the more serious cortical bone fractures which happen at hip and wrist.^ Cancer cells take up more C-11 choline than normal cells, so the pictures can be used to find cancer cells in the body.
  • Dictionary of Cancer Terms - National Cancer Institute 10 February 2010 12:52 UTC www.cancer.gov [Source type: Academic]

 ^ Compression fractures usually occur in the spine (backbone) and in bones made weak by cancer or by osteoporosis (a decrease in bone mass and density).
  • Dictionary of Cancer Terms - National Cancer Institute 10 February 2010 12:52 UTC www.cancer.gov [Source type: Academic]

 ^ It is used as a drug to increase calcium levels in the body in order to treat skeletal and tissue-related calcium deficiencies caused by kidney or thyroid disorders.
  • Dictionary of Cancer Terms - National Cancer Institute 10 February 2010 12:52 UTC www.cancer.gov [Source type: Academic]

 [citation needed]

Possible cancer prevention

A meta-analysis[39] by the international Cochrane Collaboration of two randomized controlled trials[45][46] found that calcium "might contribute to a moderate degree to the prevention of adenomatous colonic polyps".
.More recent studies were conflicting, and one which was positive for effect (Lappe, et al.^ Clinical Studies Elo et al.
  • Titanium (EHC 24, 1982) 9 January 2010 0:56 UTC www.inchem.org [Source type: Academic]

 ^ In the study by Schroeder et al.
  • Titanium (EHC 24, 1982) 9 January 2010 0:56 UTC www.inchem.org [Source type: Academic]

 ^ In the longevity study by Schroeder et al.
  • Titanium (EHC 24, 1982) 9 January 2010 0:56 UTC www.inchem.org [Source type: Academic]

 ) did control for a possible anti-carcinogenic effect of .vitamin D, which was found to be an independent positive influence from calcium-alone on cancer risk (see second study below) [47].^ The use of drugs, vitamins, or other agents to try to reduce the risk of, or delay the development or recurrence of, cancer.
  • Dictionary of Cancer Terms - National Cancer Institute 10 February 2010 12:52 UTC www.cancer.gov [Source type: Academic]

Hazards and Toxicity

.Compared to other metals, the calcium ion and most calcium compounds have low toxicity.^ A chemical compound that binds tightly to metal ions.
  • Dictionary of Cancer Terms - National Cancer Institute 10 February 2010 12:52 UTC www.cancer.gov [Source type: Academic]

 ^ Metallic titanium, titanium dioxide, and titanium tetrachloride are the compounds most widely used in industry.
  • Titanium (EHC 24, 1982) 9 January 2010 0:56 UTC www.inchem.org [Source type: Academic]

 ^ The metallic characteristics of titanium are shown in compounds such as titanium chloride, phosphate, sulfate, and nitrate, whereas the non-metallic characteristics are exhibited in a series of titanates, e.g., calcium, iron, and sodium titanates.
  • Titanium (EHC 24, 1982) 9 January 2010 0:56 UTC www.inchem.org [Source type: Academic]

 This is not surprising given the very high natural abundance of calcium compounds in the environment and in organisms. Calcium poses few, if any, serious environmental problems. Acute calcium poisoning is rare, and difficult to achieve unless calcium compounds are administered intravenously. .For example, the oral LD50 for rats for calcium carbonate and calcium chloride are 6450 [51] and 1400 mg/kg,[52] respectively.^ Studies on titanates suspended in corn oil revealed that the intraperitoneal LD 50 for rats was 3.0 g/kg body weight for barium titanate, 2.2 g/kg body weight for bismuth titanate, 5.3 g/kg for calcium titanate, and 2.0 g/kg for lead titanate.
  • Titanium (EHC 24, 1982) 9 January 2010 0:56 UTC www.inchem.org [Source type: Academic]

 ^ Titanium levels in coal and oil have been reported to average 500 and 0.1 mg/kg, respectively (Bertine & Goldberg, 1971).
  • Titanium (EHC 24, 1982) 9 January 2010 0:56 UTC www.inchem.org [Source type: Academic]
Calcium metal is hazardous because of its sometimes violent reactions with water and acids. .Calcium metal is found in some drain cleaners, where it functions to generate heat and calcium hydroxide that saponifies the fats and liquefies the proteins (e.g., hair) that block drains.^ A protein found on the surface of some bone marrow and blood cells.
  • Dictionary of Cancer Terms - National Cancer Institute 10 February 2010 12:52 UTC www.cancer.gov [Source type: Academic]

 ^ CEP-2563 dihydrochloride blocks certain proteins involved in the growth of some tumors and may kill cancer cells.
  • Dictionary of Cancer Terms - National Cancer Institute 10 February 2010 12:52 UTC www.cancer.gov [Source type: Academic]

 When swallowed calcium metal has the same effect on the mouth, esophagus and stomach, and can be fatal.[53]
.Excessive consumption of calcium carbonate antacids/dietary supplements (such as Tums) over a period of weeks or months can cause milk-alkali syndrome, with symptoms ranging from hypercalcemia to potentially fatal renal failure.^ Carcinoid tumors may spread to the liver or other sites in the body, and they may secrete substances such as serotonin or prostaglandins, causing carcinoid syndrome.
  • Dictionary of Cancer Terms - National Cancer Institute 10 February 2010 12:52 UTC www.cancer.gov [Source type: Academic]

 ^ Coral Calcium/Calcium Supplement/Calcium Citrate/Liquid Calcium, Highly Absorbable Dietary Supplement!
  • Coral Calcium/Calcium Supplement/Calcium Citrate/Liquid Calcium, Highly Absorbable Dietary Supplement! 10 February 2010 12:52 UTC www.ihealthtree.com [Source type: Academic]

 What constitutes “excessive” consumption is not well known and probably varies a great deal from person to person. .Persons who consume more than 10 grams/day of CaCO3 (=4 g Ca) are at risk of developing milk-alkali syndrome, [54] but the condition has been reported in at least one person consuming only 2.5 grams/day of CaCO3 (=1 g Ca), an amount usually considered moderate and safe.^ In science, a substance that is made up of more than one ingredient.
  • Dictionary of Cancer Terms - National Cancer Institute 10 February 2010 12:52 UTC www.cancer.gov [Source type: Academic]

 ^ The sudden and unexpected death of a healthy child who is younger than one year old, usually during sleep.
  • Dictionary of Cancer Terms - National Cancer Institute 10 February 2010 12:52 UTC www.cancer.gov [Source type: Academic]

 ^ A condition lasting for more than 6 months in which a person feels tired most of the time and may have trouble concentrating and carrying out daily activities.
  • Dictionary of Cancer Terms - National Cancer Institute 10 February 2010 12:52 UTC www.cancer.gov [Source type: Academic]

 [55]

See also

References

  1. ^ Dickson, A. G. and Goyet, C. (1994). "5". Handbook of method for the analysis of the various parameters of the carbon dioxide system in sea water, version 2. ORNL/CDIAC-74. http://cdiac.esd.ornl.gov/ftp/cdiac74/chapter5.pdf. 
  2. ^ Pauling, Linus (1970). General Chemistry. Dover Publications. p. 627. ISBN 0716701499. 
  3. ^ Tordoff, M. G. (2001). "Calcium: Taste, Intake, and Appetite". Physiological Reviews 81 (4): 1567. PMID 11581497. http://physrev.physiology.org/cgi/content/full/81/4/1567. 
  4. ^ Staff (1995). "H-K Project". Mount Wilson Observatory. http://www.mtwilson.edu/hk/. Retrieved 2006-08-10. 
  5. ^ Russell, WA; Papanastassiou, DA; Tombrello, TA (1978). "Ca isotope fractionation on the earth and other solar system materials". Geochim Cosmochim Acta 42: 1075–90. doi:10.1016/0016-7037(78)90105-9. 
  6. ^ Skulan, J; DePaolo, DJ (1999). "Calcium isotope fractionation between soft and mineralized tissues as a monitor of calcium use in vertebrates". Proc Natl Acad Sci USA 96 (24): 13709–13. doi:10.1073/pnas.96.24.13709. PMID 10570137. 
  7. ^ Skulan, J; DePaolo, D (1997). "Biological control of calcium isotopic abundances in the global calcium cycle". Geochim. Et Cosmochim. Acta 61 (12): 2505-2510. doi:10.1016/S0016-7037(97)00047-1. PMID 17463176. 
  8. ^ Skulan, J; Bullen, T; Anbar, AD; Puzas, JE; Shackelford, L; Leblanc, A; Smith, SM (2007). "Natural calcium isotopic composition of urine as a marker of bone mineral balance". Clinical Chemistry 653 (6): 1155–1158. doi:10.1373/clinchem.2006.080143. PMID 17463176. 
  9. ^ Fantle, M; DePaolo, D (2007). "Ca isotopes in carbonate sediment and pore fluid from ODP Site 807A: The Ca2+(aq)–calcite equilibrium fractionation factor and calcite recrystallization rates in Pleistocene sediments". Geochim Cosmochim Acta 71: 2524–2546. doi:10.1016/j.gca.2007.03.006. 
  10. ^ Griffith, Elizabeth M.; Paytan, Adina; Caldeira, Ken; Bullen, Thomas last5= Thomas (2008). "A Dynamic marine calcium cycle during the past 28 million years". Science 322 (12): 1671-1674. doi:10.1126/science.1163614. PMID 17463176. 
  11. ^ Zeebe (2006). "Marine carbonate chemistry". National Council for Science and the Environment. http://www.eoearth.org/article/Marine_carbonate_chemistry. Retrieved 2010-03-13. 
  12. ^ Berner, Robert (2003). "The long-term carbon cycle, fossil fuels and atmospheric composition". Nature 426: 323-326. 
  13. ^ Lide, D. R., ed. (2005), CRC Handbook of Chemistry and Physics (86th ed.), Boca Raton (FL): CRC Press, ISBN 0-8493-0486-5 
  14. ^ a b "Dietary Supplement Fact Sheet: Calcium". http://ods.od.nih.gov/factsheets/calcium.asp. 
  15. ^ "Osteoporosis Prevention - Calcium Recommendations". http://www.nof.org/prevention/calcium2.htm. 
  16. ^ Standing Committee on the Scientific Evaluation of Dietary Reference Intakes, Food and Nutrition Board, Institute of Medicine (1997). Dietary Reference Intakes for Calcium, Phosphorus, Magnesium, Vitamin D and fluoride. Washington DC: The National Academies Press. ISBN 0309064031. 
  17. ^ Curhan, Gc; Willett, Wc; Rimm, Eb; Stampfer, Mj (1993). "A prospective study of dietary calcium and other nutrients and the risk of symptomatic kidney stones.". The New England journal of medicine 328 (12): 833–8. doi:10.1056/NEJM199303253281203. PMID 8441427. 
  18. ^ Bihl G, Meyers A. (2001). "Recurrent renal stone disease-advances in pathogenesis and clinical management". Lancet 358 (9282): 651–656. doi:10.1016/S0140-6736(01)05782-8. PMID 11530173. 
  19. ^ Hall WD, Pettinger M, Oberman A (2001). "Risk factors for kidney stones in older women in the Southern United States". Am J Med Sci 322 (1): 12–18. doi:10.1097/00000441-200107000-00003. PMID 11465241. 
  20. ^ Abelow, BJ; Holford, TR; Insogna, KL (1992). "Cross-cultural association between dietary animal protein and hip fracture: a hypothesis.". Calcified tissue international 50 (1): 14–8. PMID 1739864. 
  21. ^ Hegsted, M; Schuette, SA; Zemel, MB; Linkswiler, HM (1981). "Urinary calcium and calcium balance in young men as affected by level of protein and phosphorus intake.". The Journal of nutrition 111 (3): 553–62. PMID 7205408. 
  22. ^ Kerstetter JE and Allen LH (1990). "Dietary protein increases urinary calcium". Journal of Nutrition 120 (1): 134. PMID 2406396. http://jn.nutrition.org/cgi/reprint/120/1/134.pdf. 
  23. ^ Tucker, KL; Chen, H; Hannan, MT; Cupples, LA; Wilson, PW; Felson, D; Kiel, DP (2002). "Bone mineral density and dietary patterns in older adults: the Framingham Osteoporosis Study.". The American journal of clinical nutrition 76 (1): 245–52. PMID 12081842. 
  24. ^ Schaafsma, Anne and Beelen, Gerard M (1999). "Eggshell powder, a comparable or better source of calcium than purified calcium carbonate: piglet studies" (abstract). Journal of the Science of Food and Agriculture 79 (12): 1596–1600. doi:10.1002/(SICI)1097-0010(199909)79:12<1596::AID-JSFA406>3.0.CO;2-A. http://www3.interscience.wiley.com/cgi-bin/abstract/63003036/ABSTRACT. 
  25. ^ Schaafsma A, van Doormaal JJ, Muskiet FA, Hofstede GJ, Pakan I, van der Veer E (2002). "Positive effects of a chicken eggshell powder-enriched vitamin-mineral supplement on femoral neck bone mineral density in healthy late post-menopausal Dutch women". Br. J. Nutr. 87 (3): 267–75. doi:10.1079/BJNBJN2001515. PMID 12064336. 
  26. ^ Rovenský J, Stancíková M, Masaryk P, Svík K, Istok R (2003). "Eggshell calcium in the prevention and treatment of osteoporosis". Int J Clin Pharmacol Res 23 (2-3): 83–92. PMID 15018022. 
  27. ^ "Original Wild Foods vs. Available Foods Today for Instinctos". http://www.beyondveg.com/nieft-k/instincto-guide/instincto-guide1e.shtml. 
  28. ^ "USDA National Nutrient Database". http://www.nal.usda.gov/fnic/foodcomp/search. 
  29. ^ Combs, G (2008). The Vitamins. Academic Press. p. 161. ISBN 0121834905. 
  30. ^ a b Weaver, CM (2006). "Calcium". Present Knowledge in Nutrition, 9th Ed.. I. ILSI Press. p. 377. 
  31. ^ Remington, Joseph (2005). Remington: The Science and Practice of Pharmacy. Lippincott Williams & Wilkins. pp. 1338. ISBN 0781746736. 
  32. ^ Zhao, Y; Martin, BR; Weaver, CM (2005). "Calcium bioavailability of calcium carbonate fortified soy milk is equivalent to cow's milk in young women". J. Nutr. 135 (10): 2379. PMID 16177199. http://jn.nutrition.org/cgi/content/full/135/10/2379. 
  33. ^ Martini, Ligia and Wood, Richard J (2002). "Relative bioavailability of calcium-rich dietary sources in the elderly". American Journal of Clinical Nutrition 76 (6): 1345–1350. PMID 12450902. http://www.ajcn.org/cgi/content/abstract/76/6/1345. 
  34. ^ a b Straub, D. A. (2007). "Calcium Supplementation in Clinical Practice: A Review of Forms, Doses, and Indications". Nutrition in Clinical Practice 22 (3): 286. doi:10.1177/0115426507022003286. PMID 17507729. 
  35. ^ Martin, Berdine R.; Weaver, CM; Heaney, RP; Packard, PT; Smith, DL (2002). "Calcium Absorption from Three Salts and CaSO4-Fortified Bread in Premenopausal Women". Journal of Agricultural and Food Chemistry 50 (13): 3874. doi:10.1021/jf020065g. PMID 12059174. 
  36. ^ Weaver, Connie M.; Martin, BR; Costa, NM; Saleeb, FZ; Huth, PJ (2002). "Absorption of Calcium Fumarate Salts Is Equivalent to Other Calcium Salts When Measured in the Rat Model". Journal of Agricultural and Food Chemistry 50 (17): 4974. doi:10.1021/jf0200422. PMID 12166992. 
  37. ^ Harding, Anne. "Calcium May Help With Weight Loss". http://www.rxalternativemedicine.com/headlines_news.php#headline77. Retrieved 2007-07-10. 
  38. ^ Dawson-Hughes B, Harris SS, Krall EA, Dallal GE (1997). "Effect of calcium and vitamin D supplementation on bone density in men and women 65 years of age or older". N. Engl. J. Med. 337 (10): 670–6. doi:10.1056/NEJM199709043371003. PMID 9278463. 
  39. ^ a b Weingarten MA, Zalmanovici A, Yaphe J (2005). "Dietary calcium supplementation for preventing colorectal cancer, adenomatous polyps and calcium metabolisism disorder.". Cochrane database of systematic reviews (Online) (3): CD003548. doi:10.1002/14651858.CD003548.pub3. PMID 16034903. 
  40. ^ Jackson RD, LaCroix AZ, Gass M (2006). "Calcium plus vitamin D supplementation and the risk of fractures". N. Engl. J. Med. 354 (7): 669–83. doi:10.1056/NEJMoa055218. PMID 16481635. 
  41. ^ Grant AM, Avenell A, Campbell MK (2005). "Oral vitamin D3 and calcium for secondary prevention of low-trauma fractures in elderly people (Randomised Evaluation of Calcium Or vitamin D, RECORD): a randomised placebo-controlled trial". Lancet 365 (9471): 1621–8. doi:10.1016/S0140-6736(05)63013-9. PMID 15885294. 
  42. ^ Porthouse J, Cockayne S, King C (2005). "Randomised controlled trial of calcium and supplementation with cholecalciferol (vitamin D3) for prevention of fractures in primary care". BMJ 330 (7498): 1003. doi:10.1136/bmj.330.7498.1003. PMID 15860827. 
  43. ^ Prince RL, Devine A, Dhaliwal SS, Dick IM (2006). "Effects of calcium supplementation on clinical fracture and bone structure: results of a 5-year, double-blind, placebo-controlled trial in elderly women". Arch. Intern. Med. 166 (8): 869–75. doi:10.1001/archinte.166.8.869. PMID 16636212. 
  44. ^ Fletcher RH (2006). "Calcium plus vitamin D did not prevent hip fracture or colorectal cancer in postmenopausal women" (subscription required). ACP J. Club 145 (1): 4–5. PMID 16813354. http://www.acpjc.org/Content/145/1/issue/ACPJC-2006-145-1-004.htm. 
  45. ^ Baron JA, Beach M, Mandel JS (1999). "Calcium supplements for the prevention of colorectal adenomas. Calcium Polyp Prevention Study Group". N. Engl. J. Med. 340 (2): 101–7. doi:10.1056/NEJM199901143400204. PMID 9887161. 
  46. ^ Bonithon-Kopp C, Kronborg O, Giacosa A, Räth U, Faivre J (2000). "Calcium and fibre supplementation in prevention of colorectal adenoma recurrence: a randomised intervention trial. European Cancer Prevention Organisation Study Group". Lancet 356 (9238): 1300–6. doi:10.1016/S0140-6736(00)02813-0. PMID 11073017. 
  47. ^ Lappe, Jm; Travers-Gustafson, D; Davies, Km; Recker, Rr; Heaney, Rp (2007). "Vitamin D and calcium supplementation reduces cancer risk: results of a randomized trial." (Free full text). The American journal of clinical nutrition 85 (6): 1586–91. PMID 17556697. http://www.ajcn.org/cgi/pmidlookup?view=long&pmid=17556697. 
  48. ^ Wactawski-Wende J, Kotchen JM, Anderson GL (2006). "Calcium plus vitamin D supplementation and the risk of colorectal cancer". N. Engl. J. Med. 354 (7): 684–96. doi:10.1056/NEJMoa055222. PMID 16481636. 
  49. ^ Lappe JM, Travers-Gustafson D, Davies KM, Recker RR, Heaney RP (2007). "Vitamin D and calcium supplementation reduces cancer risk: results of a randomized trial". Am. J. Clin. Nutr. 85 (6): 1586–91. PMID 17556697. 
  50. ^ Lin J, Manson JE, Lee IM, Cook NR, Buring JE, Zhang SM (2007). "Intakes of calcium and vitamin d and breast cancer risk in women". Arch. Intern. Med. 167 (10): 1050–9. doi:10.1001/archinte.167.10.1050. PMID 17533208. 
  51. ^ Lewis, R. J. (1996), Sax's Dangerous Properties of Industrial Materials. (9th ed.), New York, NY: Van Nostrand Reinhold, pp. 635 
  52. ^ ITII. Toxic and Hazardous Industrial Chemicals Safety Manual, Tokyo, Japan: The International Technical Information Institute, 1988, pp. 101 
  53. ^ Rumack BH. POISINDEX. Information System Micromedex, Inc., Englewood, CO, 2010; CCIS Volume 143. Hall AH and Rumack BH (Eds)
  54. ^ Beall DP, Henslee HB, Webb HR, Scofield RH (May 2006). "Milk-alkali syndrome: a historical review and description of the modern version of the syndrome". Am. J. Med. Sci. 331 (5): 233–42. doi:10.1097/00000441-200605000-00001. PMID 16702792. http://meta.wkhealth.com/pt/pt-core/template-journal/lwwgateway/media/landingpage.htm?an=00000441-200605000-00001. 
  55. ^ Picolos MK and Orlander PR (2005). "Calcium carbonate toxicity: The updated milk-alkali syndrome; report of 3 cases and review of the literature". Endocrine Practice 4 (11): 272-80. 

Further reading

  • Rebecca J. Donatelle. Health, The Basics. 6th ed. .San Francisco: Pearson Education, Inc.^ Paper presented at the Annual Meeting of the American Educational Research Association, San Francisco, CA. (ERIC Document Reproduction Service No.
    • ESOL ESOL TAPESTRY 11 September 2009 9:53 UTC tapestry.usf.edu [Source type: Academic]

     2005.

External links

Periodic table
H   He
Li Be   B C N O F Ne
Na Mg   Al Si P S Cl Ar
K Ca Sc   Ti V Cr Mn Fe Co Ni Cu Zn Ga Ge As Se Br Kr
Rb Sr Y   Zr Nb Mo Tc Ru Rh Pd Ag Cd In Sn Sb Te I Xe
Cs Ba La Ce Pr Nd Pm Sm Eu Gd Tb Dy Ho Er Tm Yb Lu Hf Ta W Re Os Ir Pt Au Hg Tl Pb Bi Po At Rn
Fr Ra Ac Th Pa U Np Pu Am Cm Bk Cf Es Fm Md No Lr Rf Db Sg Bh Hs Mt Ds Rg Cn Uut Uuq Uup Uuh Uus Uuo
Alkali metals Alkaline earth metals Lanthanoids Actinoids Transition metals Other metals Metalloids Other nonmetals Halogens Noble gases

1911 encyclopedia

Up to date as of January 14, 2010

From LoveToKnow 1911

.CALCIUM [[[symbol]] Ca, atomic weight 40.0 (0= 16)], a metallic chemical element, so named by Sir Humphry Davy from its occurrence in chalk (Latin calx). It does not occur in nature in the free state, but in combination it is widely and abundantly diffused.^ Ionic calcium (Ca++) is the only physiologically active form of this element.
  • Calcium 10 February 2010 12:52 UTC goldrust.net [Source type: FILTERED WITH BAYES]

 ^ Total molecular weight of ionic calcium is 40.09 mg.
  • Calcium 10 February 2010 12:52 UTC goldrust.net [Source type: FILTERED WITH BAYES]

 ^ A 1,000 mg tablet of calcium lactate will chemically break down to 860 mg of milk sugar or lactose and 140 mg (or 14%) of elemental calcium.
  • Calcium 10 February 2010 12:52 UTC goldrust.net [Source type: FILTERED WITH BAYES]

 .Thus the sulphate constitutes the minerals anhydrite, alabaster, gypsum, and selenite; the carbonate occurs dissolved in most natural waters and as the minerals chalk, marble, calcite, aragonite; also in the double carbonates such as dolomite, bromlite, barytocalcite; the fluoride as fluorspar; the fluophosphate constitutes the mineral apatite; while all the more important mineral silicates contain a proportion of this element.^ COAL. In its most general sense the term " coal " includes all varieties of carbonaceous minerals used as fuel , but it is now usual in England to restrict it to the particular varieties of such minerals occurring in the older Carboniferous formations.

 ^ Mineral details: Tremolite, amphibole group, double-chain silicate.
  • Pictures, stories, and facts about the element Calcium in the Periodic Table 10 February 2010 12:52 UTC periodictable.com [Source type: General]

 ^ Mineral salts are a compound containing a mineral element (which is the mineral normally listed on a supplement label) and some other substance it is chemically bound to.
  • Calcium 10 February 2010 12:52 UTC goldrust.net [Source type: FILTERED WITH BAYES]

Extraction

.Calcium oxide or lime has been known from a very remote period, and was for a long time considered to be an elementary or undecomposable earth.^ The lung is considered to be the primary target organ in man and the residence time of titanium dioxide in the lung has been regarded as long (ICRP, 1959).
  • Titanium (EHC 24, 1982) 9 January 2010 0:56 UTC www.inchem.org [Source type: Academic]

 ^ Inflammation of the prostate gland that is caused by a bacterial infection and that continues or gets worse over a long period of time.
  • Dictionary of Cancer Terms - National Cancer Institute 10 February 2010 12:52 UTC www.cancer.gov [Source type: Academic]

 ^ A condition of the prostate gland that continues or gets worse over a long period of time.
  • Dictionary of Cancer Terms - National Cancer Institute 10 February 2010 12:52 UTC www.cancer.gov [Source type: Academic]

 This view was questioned in the 18th century, and in 1808 Sir Humphry Davy (Phil. Trans., 1808, p. 303) was able to show that lime was a combination of a metal and oxygen. .His attempts at isolating this metal were not completely successful; in fact, metallic calcium remained a laboratory curiosity until the beginning of the 10th century.^ Nodules of very high-purity, completely un-oxidized calcium metal in an argon-filled ampule.
  • Pictures, stories, and facts about the element Calcium in the Periodic Table 10 February 2010 12:52 UTC periodictable.com [Source type: General]

 ^ I still can't get over the fact that calcium is a metal , not a white chalky thing you eat to make your bones strong.
  • Pictures, stories, and facts about the element Calcium in the Periodic Table 10 February 2010 12:52 UTC periodictable.com [Source type: General]

 .Davy, inspired by his successful isolation of the metals sodium and potassium by the electrolysis of their hydrates, attempted to decompose a mixture of lime and mercuric oxide by the electric current; an amalgam of calcium was obtained, but the separation of the mercury was so difficult that even Davy himself was not sure as to whether he had obtained pure metallic calcium.^ Calcium, potassium, sodium, Cyanide salts/ [NIOSH; Criteria Document: Hydrogen Cyanide and Cyanide Salts p.190 (1976) DHEW Pub.

 ^ Dose-response curves for the ventilatory effects induced by iv injections of sodium cyanide were obtained before and after successive denervations of peripheral chemoreceptors, in different sequences.

 ^ PEER REVIEWED** Methods of Manufacturing: Sodium cyanide can be prepared by heating sodium amide with carbon, by melting sodium chloride and calcium cyanamide together in an electric furnace ...

 .Electrolysis of lime or calcium chloride in contact with mercury gave similar results.^ Contact with water resulted in severe burns due to the exothermic reaction between titanium tetra chloride and water.
  • Titanium (EHC 24, 1982) 9 January 2010 0:56 UTC www.inchem.org [Source type: Academic]

 Bunsen (Ann., 1854, 92, p. .248) was more successful when he electrolysed calcium chloride moistened with hydrochloric acid; and A. Matthiessen (Jour.^ Magnesium chloride is magnesium ammonium chloride processed with hydrochloric acid.
  • Calcium 10 February 2010 12:52 UTC goldrust.net [Source type: FILTERED WITH BAYES]

 ^ The ionized forms of calcium, such as citrate and citrate malate, tend to be more soluble and have a greater absorption rate, especially in people who are deficient in hydrochloric acid.

 Chem. Soc., 1856, p. .28) obtained the metal by electrolysing a mixture of fused calcium and sodium chlorides.^ Dicalcium phosphate is the rock known as monetite, but can be made from calcium chloride and sodium phosphate.
  • Calcium 10 February 2010 12:52 UTC goldrust.net [Source type: FILTERED WITH BAYES]

 ^ PEER REVIEWED** Mixtures of sodium cyanide with sodium chloride or carbonate for special uses are also marketed.

 ^ PEER REVIEWED** Methods of Manufacturing: Sodium cyanide can be prepared by heating sodium amide with carbon, by melting sodium chloride and calcium cyanamide together in an electric furnace ...

 .Henri Moissan obtained the metal of 99% purity by electrolysing calcium iodide at a low red heat, using a nickel cathode and a graphite anode; he also showed that a more convenient process consisted in heating the iodide with an excess of sodium, forming an amalgam of the product, and removing the sodium by means of absolute alcohol (which has but little action on calcium), and the mercury by distillation.^ Calcium iodide is calcium carbonate processed with iodine.
  • Calcium 10 February 2010 12:52 UTC goldrust.net [Source type: FILTERED WITH BAYES]

 ^ Produced in large quantities and used as metal in heat exchanger in atomic reactors.
  • Mineral Species sorted by the element Na Sodium 6 January 2010 8:54 UTC webmineral.com [Source type: FILTERED WITH BAYES]

 ^ If the cyanide ion is present in excess, complex metallocyanides may form; however, if metals are prevalent, simple metal cyanides may form.
.The electrolytic isolation of calcium has been carefully investigated, and this is the method followed for the commercial production of the metal.^ Present commercial production by this method yields a titanium alloy of 99.5% purity that differs in hardness and strength from the pure titanium metal prepared from the thermal decomposition of titanium iodide (TiI 4 ).
  • Titanium (EHC 24, 1982) 9 January 2010 0:56 UTC www.inchem.org [Source type: Academic]

 ^ The principal method for the commercial production of titanium sponge metal is the Kroll process, which involves the reduction of titanium tetrachloride with magnesium metal in an inert atmosphere.
  • Titanium (EHC 24, 1982) 9 January 2010 0:56 UTC www.inchem.org [Source type: Academic]

 In 1902 W. Borchers and L. Stockem (Zeit. filr Electrochemie, 1902, p. .8757) obtained the metal of 90% purity by electrolysing calcium chloride at a temperature of about 780°, using an iron cathode, the anode being the graphite vessel in which the electrolysis was carried out.^ Individuals concerned about potential calcium deficiency due to using triamterene should consult their prescribing physician and/or a nutritionally trained healthcare professional.

 ^ Nodules of very high-purity, completely un-oxidized calcium metal in an argon-filled ampule.
  • Pictures, stories, and facts about the element Calcium in the Periodic Table 10 February 2010 12:52 UTC periodictable.com [Source type: General]

 ^ Whether loop diuretics increases the bone turn-over by augmenting the urinary calcium excretion is more controversial as only few studies have been carried out on loop diuretics.

 In the same year, 0. Ruff and W. Plato (Ber. 1902, 35, p. .3612) employed a mixture of calcium chloride (ioo parts) and fluorspar (16.5 parts), which was fused in a porcelain crucible and electrolysed with a carbon anode and an iron cathode.^ Calcium chloride is calcium carbonate and chlorine and is the by product of the Solvay ammonia-soda process.
  • Calcium 10 February 2010 12:52 UTC goldrust.net [Source type: FILTERED WITH BAYES]

 ^ PEER REVIEWED** Mixtures of sodium cyanide with sodium chloride or carbonate for special uses are also marketed.

 ^ PEER REVIEWED** Methods of Manufacturing: Sodium cyanide can be prepared by heating sodium amide with carbon, by melting sodium chloride and calcium cyanamide together in an electric furnace ...

 .Neither of these processes admitted of commercial application, but by a modification of Ruff and Plato's process, W. Ruthenau and C. Suter have made the metal commercially available.^ Prototypes to Mill runs, off the shelf or custom made, our diverse process capabilities make All Metal Sales, Inc.

 These chemists electrolyse either pure calcium chloride, or a mixture of this salt with fluorspar, in a graphite vessel which servos as the anode. The cathode consists of an iron rod which can be gradually raised. .On electrolysis a layer of metallic calcium is formed at the lower end of this rod on the surface of the electrolyte; the rod is gradually raised, the thickness of the layer increases, and ultimately a rod of metallic calcium, forming, as it were, a continuation of the iron cathode, is obtained.^ A device used to deliver drugs directly to the cervix (the lower, narrow end of the uterus that forms a canal between the uterus and vagina).
  • Dictionary of Cancer Terms - National Cancer Institute 10 February 2010 12:52 UTC www.cancer.gov [Source type: Academic]

 ^ The sugar fed into the upper end of the cylinder gradually works its way down to the lower, showering itself upon the heated central cylinder.

 ^ Cholestyramine-fed rats had a net negative balance for calcium and a lower net positive balance for magnesium, iron, and zinc than the controls.

 This is the form in which calcium is put on the market.
.An idea as to the advance made by this method is recorded in the variation in the price of calcium.^ Simultaneous intracellular recordings of presynaptic and postsynaptic resting action potentials were made during bath application of various metabolic inhibitors including sodium cyanide.

 At the beginning of 1904 it was quoted at 5s. per gram, £250 per kilogram or £Iio per pound; about a year later the price was reduced to 21s. per kilogram, or its. per kilogram in quantities of ioo kilograms. .These quotations apply to Germany; in the United Kingdom the price (1905) varied from 27s.^ PEER REVIEWED** Pulmonary aluminosis is a disease first seen in Germany between 1938 and 1945 which then reappeared in the United Kingdom between 1952 and 1959.

 to 30s. per kilogram (12s. to 13s. per lb.).

Properties

.A freshly prepared surface of the metal closely resembles zinc in appearance, but on exposure to the air it rapidly tarnishes, becoming yellowish and ultimately grey or white in colour owing to the formation of a surface layer of calcium hydrate.^ Although turbinado closely resembles refined white sugar in sweetening ability and composition, it cannot always be substituted in recipes.

 ^ It varies in colour from a light brown in the newest lignites to a pure black, often with a bluish or yellowish tint in the more compact anthracite of the older formations.

 ^ It is estimated that over half of all non-permanent white or light-coloured surface coatings include a titanium dioxide level of 0.1-0.3 kg/litre.
  • Titanium (EHC 24, 1982) 9 January 2010 0:56 UTC www.inchem.org [Source type: Academic]

 .A faint smell of acetylene may be perceived during the oxidation in moist air; this is probably due to traces of calcium carbide.^ Calcium, as well as food and dairy products containing high concentrations of calcium, may decrease the absorption of tetracyclines due to chelate formation in the gut.
.It is rapidly acted on by water, especially if means are taken to remove the layer of calcium hydrate formed on the metal; alcohol acts very slowly.^ A series of x-ray pictures of the esophagus taken after a patient drinks a liquid containing barium sulfate (a form of the silver-white metallic element barium).
  • Dictionary of Cancer Terms - National Cancer Institute 10 February 2010 12:52 UTC www.cancer.gov [Source type: Academic]

 ^ All sugars are colourless solids or syrups, which char on strong heating ; they are soluble in water, forming sweet solutions but difficultly soluble in alcohol .

 ^ Nodules of very high-purity, completely un-oxidized calcium metal in an argon-filled ampule.
  • Pictures, stories, and facts about the element Calcium in the Periodic Table 10 February 2010 12:52 UTC periodictable.com [Source type: General]

 In its chemical properties it closely resembles barium and strontium, and to some degree magnesium; these four elements comprise the so-called metals of the "alkaline earths." It combines directly with most elements, including nitrogen; this can be taken advantage of in forming almost a perfect vacuum, the oxygen combining to form the oxide, CaO, and the nitrogen to form the nitride, Ca 3 N 2. Several of its physical properties have been determined by K. Arndt (Ber., 1904, 37, p. 4733). .The metal as prepared by electrolysis generally contains traces of aluminium and silica.^ The American Association of Petroleum Geologists produces a technical Bulletin which generally contains articles on the geological origin of oil, and trying to trace the source rocks.
  • The Origin of Oil—A Creationist Answer - Answers in Genesis 1 February 2010 3:34 UTC www.answersingenesis.org [Source type: FILTERED WITH BAYES]

 ^ Klein & Russel (1973) reported that soils around a coal- burning power plant contained higher levels of trace metals than surrounding areas.
  • Titanium (EHC 24, 1982) 9 January 2010 0:56 UTC www.inchem.org [Source type: Academic]

 Its specific gravity is 1 54, and after remelting 1 56; after distillation it is 1.52. It melts at about 800°, but sublimes at a lower temperature. Compounds. - Calcium hydride, obtained by heating electrolytic calcium in a current of hydrogen, appears in commerce under the name hydrolite. Water decomposes it to give hydrogen free from ammonia and acetylene, i gram yielding about loo ccs. of gas (Prats Aymerich, Abst. J. C. S., 1907, ii p. 460). .Calcium forms two oxides - the monoxide, CaO, and the dioxide, CaO 2. The monoxide and its hydrate are more familiarly known as lime (q.v.^ Quicklime is calcium oxide (CaO).
  • Pictures, stories, and facts about the element Calcium in the Periodic Table 10 February 2010 12:52 UTC periodictable.com [Source type: General]

 ^ The ionized forms of calcium, such as citrate and citrate malate, tend to be more soluble and have a greater absorption rate, especially in people who are deficient in hydrochloric acid.

 ) and slakedlime. The dioxide was obtained as the hydrate, CaO 2.8H,0, by P. Thenard (Ann. Chim. Phys., 1818, 8, p. 213), who precipitated lime-water with hydrogen peroxide. .It is permanent when dry; on heating to 130° C. it loses water and gives the anhydrous dioxide as an unstable, pale buff-coloured powder, very sparingly soluble in water.^ V7 766]**PEER REVIEWED** When heated in a dry carbon dioxide atmosphere, sodium cyanide fuses without much decomposition.

 ^ All sugars are colourless solids or syrups, which char on strong heating ; they are soluble in water, forming sweet solutions but difficultly soluble in alcohol .

 ^ Sometimes it is almost pasty, and crumbles to powder when dried, so as to be susceptible of use as a pigment, forming the colour known as Cologne earth, which resembles umber or sepia .

 It is used as an antiseptic and oxidizing agent.
.Whereas calcium chloride, bromide, and iodide are deliquescent solids, the fluoride is practically insoluble in water; this is a parallelism to the soluble silver fluoride, and the insoluble chloride, bromide and iodide.^ The metallic characteristics of titanium are shown in compounds such as titanium chloride, phosphate, sulfate, and nitrate, whereas the non-metallic characteristics are exhibited in a series of titanates, e.g., calcium, iron, and sodium titanates.
  • Titanium (EHC 24, 1982) 9 January 2010 0:56 UTC www.inchem.org [Source type: Academic]

 .Calcium fluoride, CaF2, constitutes the mineral fluor-spar, and is prepared artificially as an insoluble white powder by precipitating a solution of calcium chloride with a soluble fluoride.^ Back The soil would have to include a range of soluble minerals and compounds of calcium, potassium, phosphorus and the nitrates so that farming could continue.
  • The Origin of Oil—A Creationist Answer - Answers in Genesis 1 February 2010 3:34 UTC www.answersingenesis.org [Source type: FILTERED WITH BAYES]

 ^ By increasing the molarity of the solutions, the binding to the resins of vitamin B12-intrinsic factor complex and of calcium chloride was completely inhibited.

 ^ PEER REVIEWED** Methods of Manufacturing: Sodium cyanide can be prepared by heating sodium amide with carbon, by melting sodium chloride and calcium cyanamide together in an electric furnace ...

 .One part dissolves in 26,000 parts of water.^ A sugar solution begins with sugar, partially dissolved in at least one-third its weight of cold water.

 .Calcium chloride, CaCl 2, occurs in many natural waters, and as a by-product in the manufacture of carbonic acid (carbon dioxide), and potassium chlorate.^ Separate from water, acids, carbon dioxide.

 ^ The oxygen might be expected to react and form carbon dioxide and water.
  • The Origin of Oil—A Creationist Answer - Answers in Genesis 1 February 2010 3:34 UTC www.answersingenesis.org [Source type: FILTERED WITH BAYES]

 ^ A metallic element that occurs naturally in tiny amounts in air, water, soil, and food.
  • Dictionary of Cancer Terms - National Cancer Institute 10 February 2010 12:52 UTC www.cancer.gov [Source type: Academic]

 .Aqueous solutions deposit crystals containing 2, 4 or 6 molecules of water.^ The water in the reservoir contains moderately large amounts of barium and strontium, which would be unusual if the deposition took place within a normal seawater environment.
  • The Origin of Oil—A Creationist Answer - Answers in Genesis 1 February 2010 3:34 UTC www.answersingenesis.org [Source type: FILTERED WITH BAYES]

 .Anhydrous calcium chloride, prepared by heating the hydrate to 200° (preferably in a current of hydrochloric acid gas, which prevents the formation of any oxychloride), is very hygroscopic, and is used as a desiccating agent.^ The air was continually returned and circulated until it was too much contaminated with carbonic acid to be further used, a condition which limited the use of the apparatus to a very short period.

 ^ PEER REVIEWED** Contact with acids and acid salts causes immediate formation of toxic and flammable hydrogen cyanide gas.

 ^ However, administration of phenytoin with calcium preparations should be separated by at least 3 hours to prevent a decrease in phenytoin absorption.

 It fuses at 723°. It combines with gaseous ammonia and forms crystalline compounds with certain alcohols. .The crystallized salt dissolves very readily in water with a considerable absorption of heat; hence its use in forming "freezing mixtures."^ As the amount of ash varies very considerably in different coals, and stands in no relation to the proportion of the other constituents, it is necessary in forming a chemical classification to compute the results of analysis after deduction of the ash and hygroscopic water.

 ^ A procedure that uses gold salts (a salt form of the metal element gold) to treat diseases, such as rheumatoid arthritis.
  • Dictionary of Cancer Terms - National Cancer Institute 10 February 2010 12:52 UTC www.cancer.gov [Source type: Academic]

 ^ Titanium does not easily atomize and has a tendency to form refractory oxides, which may influence the use of atomic absorption assays.
  • Titanium (EHC 24, 1982) 9 January 2010 0:56 UTC www.inchem.org [Source type: Academic]

 A temperature of - 55° C. is obtained by mixing Jo parts of the hexahydrate with 7 parts of snow. .A saturated solution of calcium chloride contains 325 parts of CaC1 2 to ioo of water at the boiling point (179.5°).^ I'm not clear on what they were meant to be used for, but it sounds like the idea was to drop the calcium chunks into water or perhaps an acid solution, at which point they will generate a steady stream of hydrogen gas until consumed.
  • Pictures, stories, and facts about the element Calcium in the Periodic Table 10 February 2010 12:52 UTC periodictable.com [Source type: General]

 ^ As long as there is a lot of water in the syrup, the temperature does not rise much above the boiling point of the water.

 ^ A supersaturated sugar solution contains more sugar than the water can dissolve at room temperature.

 .Calcium iodide and bromide are white deliquescent solids and closely resemble the chloride.^ PEER REVIEWED** WHITE SOLID IN FORM OF GRANULES, FLAKES, OR EGGS (RESEMBLING CHICKEN EGGS) [National Fire Protection Association.
Chloride of lime or "bleaching powder" is a calcium chlorhypochlorite or an equimolecular mixture of the chloride and hypochlorite (see Alkali Manufacture and Bleaching). Calcium carbide, CaC2, a compound of great industrial importance as a source of acetylene, was first prepared by F. Wohler. .It is now manufactured by heating lime and carbon in the electric furnace (see Acetylene).^ Right now decision-makers in Congress are attempting to pass strong legislation to reduce carbon pollution from the electrical sector.
  • Alltop - Top Water News 28 January 2010 1:01 UTC water.alltop.com [Source type: General]

 ^ PEER REVIEWED** Methods of Manufacturing: Sodium cyanide can be prepared by heating sodium amide with carbon, by melting sodium chloride and calcium cyanamide together in an electric furnace ...

 ^ Electric Heat Furnaces .
  • Titanium Information and Resources 9 January 2010 0:56 UTC www.titanium.cc [Source type: Reference]
  • Rubber Molding Information and Resources 30 January 2010 3:18 UTC www.rubbermolding.org [Source type: Reference]
  • Aluminum Suppliers Information and Resources 10 February 2010 11:10 UTC www.aluminumsuppliers.net [Source type: Reference]

 .Heated in chlorine or with bromine, it yields carbon and calcium chloride or bromide; at a dull red heat it burns in oxygen, forming calcium carbonate, and it becomes incandescent in sulphur vapour at 500°, forming calcium sulphide and carbon disulphide.^ The oxygen might be expected to react and form carbon dioxide and water.
  • The Origin of Oil—A Creationist Answer - Answers in Genesis 1 February 2010 3:34 UTC www.answersingenesis.org [Source type: FILTERED WITH BAYES]

 ^ Carbon monoxide prevents red blood cells from carrying enough oxygen for cells and tissues to live.
  • Dictionary of Cancer Terms - National Cancer Institute 10 February 2010 12:52 UTC www.cancer.gov [Source type: Academic]

 ^ In the chloride process (Katari et al., 1977), titanium tetrachloride is oxidized with air or oxygen and the resulting titanium dioxide calcined at approximately 500-600C to remove residual chlorine and any hydrogen chloride that may have formed in the reaction.
  • Titanium (EHC 24, 1982) 9 January 2010 0:56 UTC www.inchem.org [Source type: Academic]

 .Heated in the electric furnace in a current of air, it yields calcium cyanamide (see Cyanamide).^ PEER REVIEWED** Methods of Manufacturing: Sodium cyanide can be prepared by heating sodium amide with carbon, by melting sodium chloride and calcium cyanamide together in an electric furnace ...
.Calcium carbonate, CaCO 3, is of exceptionally wide distribution in both the mineral and animal kingdoms.^ The interaction between tetracycline and calcium-rich foods such as milk products exerts adverse effects on both and teeth that are well documented and widely recognized.

 ^ CONJUGATION IS CATALYZED BY THE ENZYME RHODANESE WHICH IS WIDELY DISTRIBUTED IN MOST ANIMAL TISSUES EXCEPT BLOOD, LIVER BEING PARTICULARLY ACTIVE. ...

 It constitutes the bulk of the chalk deposits and limestone rocks; it forms over one-half of the mineral dolomite and the rock magnesium limestone; it occurs also as the dimorphous minerals aragonite (q.v.) and calcite (q.v.). Tuff and travertine are calcareous deposits found in volcanic districts. .Most natural waters contain it dissolved in carbonic acid; this confers "temporary hardness" on the water.^ Separate from water, acids, carbon dioxide.

 ^ OTHER SYRUPS Corn Syrup: Containing 24 percent water, corn syrup is obtained by partial hydrolysis of cornstarch by acid, alkaline or enzymatic catalysts.

 ^ With partially refined sugar that still contains its natural molasses the water will remain clear and the sugar crystals brown.

 The dissipation of the dissolved carbon dioxide results in the formation of "fur" in kettles or boilers, and if the solution is falling, as from the roof of a cave, in the formation of stalactites and stalagmites. In the animal kingdom it occurs as both calcite and aragonite in the tests of the foraminifera, echinoderms, brachiopoda, and mollusca; also in the skeletons of sponges and corals. .Calcium carbonate is obtained as a white precipitate, almost insoluble in water (1 part requiring Io,000 of water for soluticn), by mixing solutions of a carbonate and a calcium salt.^ ELIK, E.E. (1969) [The processing of TiO 2 manufacture waste water for obtaining commercial gypsum and a denser precipitate.
  • Titanium (EHC 24, 1982) 9 January 2010 0:56 UTC www.inchem.org [Source type: Academic]

 ^ The pans are provided with steam worms to keep the mass hot as required, and with mechanical stirrers to keep it in movement and thoroughly mixed with the water and sweet water which are added to the sugar to obtain a solution of the specific gravity desired.

 ^ Water is fast becoming a hot topic for every part of society, and in the coming decade, water will require new perspectives, more comprehensive information and innovative action.
  • Alltop - Top Water News 28 January 2010 1:01 UTC water.alltop.com [Source type: General]

 .Hot or dilute cold solutions deposit minute orthorhombic crystals of aragonite, cold saturated or moderately strong solutions, hexagonal (rhombohedral) crystals of calcite.^ It is important to know that the Baumé reading in a cold solution measures slightly higher than the same solution when hot.

 ^ A saturated sugar solution contains the maximum amount of sugar possible at room temperature without precipitating out into crystals.

 Aragonite is the least stable form; crystals have been found altered to calcite.
.Calcium nitride, Ca 3 N 2, is a greyish-yellow powder formed by heating calcium in air or nitrogen; water decomposes it with evolution of ammonia (see H. Moissan, Compt.^ Calcium is relatively reactive, and will decompose on contact with water, but it's stable enough to stay shiny with just this minimal coating of oil.
  • Pictures, stories, and facts about the element Calcium in the Periodic Table 10 February 2010 12:52 UTC periodictable.com [Source type: General]

 ^ Titanium tetrachloride is a liquid, which is stable in dry air, but decomposes in cold water to form titanium oxide and hydrochloric acid.
  • Titanium (EHC 24, 1982) 9 January 2010 0:56 UTC www.inchem.org [Source type: Academic]

 ^ QC REVIEWED** Explosive Limits & Potential: FORMS EXPLOSIVE MIXTURES IN A DUST CLOUD IN AIR. BULK DUST WHEN DAMP WITH WATER MAY HEAT SPONTANEOUSLY. HAZARD GREATER AS FINENESS INCREASES. [Fire Protection Guide to Hazardous Materials.

 Rend., 127, p. 497). .Calcium nitrate, Ca(N0,)2.4H20, is a highly deliquescent salt, crystallizing in monoclinic prisms, and occurring in various natural waters, as an efflorescence in limestone caverns, and in the neighbourhood of decaying nitrogenous organic matter.^ When slowly crystallized it forms large monoclinic prisms which are readily soluble in water but difficultly soluble in alcohol.

 ^ With partially refined sugar that still contains its natural molasses the water will remain clear and the sugar crystals brown.

 ^ A metallic element that occurs naturally in tiny amounts in air, water, soil, and food.
  • Dictionary of Cancer Terms - National Cancer Institute 10 February 2010 12:52 UTC www.cancer.gov [Source type: Academic]

 Hence its synonyms, "wall-saltpetre" and "lime-saltpetre"; from its disintegrating action on mortar, it is sometimes referred to as "saltpetre rot." The anhydrous nitrate, obtained by heating the crystallized salt, is very phosphorescent, and constitutes "Baldwin's phosphorus." A basic nitrate, Ca(NO 3)2 Ca(OH) 2.3H 2 0, is obtained by dissolving calcium hydroxide in a solution of the normal nitrate.
.Calcium phosphide, Ca 3 P 2, is obtained as a reddish substance by passing phosphorus vapour over strongly heated lime.^ In 1861 Butlerow obtained a sugar-like substance, methylenitan, by digesting trioxymethylene, the solid polymer of formaldehyde, with lime.

 .Water decomposes it with the evolution of spontaneously inflammable hydrogen phosphide; hence its use as a marine signal fire ("Holmes lights"), (see L. Gattermann and W. Haussknecht, Ber., 1890, 23, p.^ Coals richer in hydrogen, on the other hand, are more useful for burning in open fires - smiths' forges and furnaces - where a long flame is required.

 ^ Use water spray to keep fire-exposed containers cool.

 1176, and H. Moissan, Compt. Rend., 128, p. 787).
.Of the calcium orthophosphates, the normal salt, Ca3(P04)2, is the most important.^ Serum calcium is extremely important for maintenance of normal cellular functions and is regulated by the major calciotropic hormones, parathyroid hormone (PTH), 1,25-dihydroxy-vitamin D and calcitonin.

 It is the principal inorganic constituent of bones, and hence of the "bone-ash" of commerce (see Phosphorus); it occurs with fluorides in the mineral apatite (q.v.); and the concretions known as coprolites largely consist of this salt. It also constitutes the minerals ornithite, Ca3(P04)2 2H20, osteolite and sombrerite. The mineral brushite, CaHPO 4.2H 2 0, which is isomorphous with the acid arsenate pharmacolite, CaHAs04.2H20, is an acid phosphate, and assumes monoclinic forms. .The normal salt may be obtained artificially, as a white gelatinous precipitate which shrinks greatly on drying, by mixing solutions of sodium hydrogen phosphate, ammonia, and calcium chloride.^ This may result in reduced levels of 25-hydroxycholecalciferol and 1,25-dihydroxycholecalciferol which are necessary for normal absorption of calcium.

 ^ By increasing the molarity of the solutions, the binding to the resins of vitamin B12-intrinsic factor complex and of calcium chloride was completely inhibited.

 ^ Calcium, potassium, sodium, Cyanide salts/ [NIOSH; Criteria Document: Hydrogen Cyanide and Cyanide Salts p.190 (1976) DHEW Pub.

 .Crystals may be obtained by heating di-calcium pyrophosphate, Ca2P207, with water under pressure.^ Containers may explode when heated or contaminated with water.

 ^ Reaction with water may generate much heat which will increase the concentration of fumes in the air.

 ^ A portion of this may be got by the process known as robbing the pillars, but the coal so obtained is liable to be very much crushed from the pressure of the superincumbent strata.

 .It is insoluble in water; slightly soluble in solutions of carbonic acid and common salt, and readily soluble in concentrated hydrochloric and nitric acid.^ Separate from water, acids, carbon dioxide.

 ^ An ashing step with concentrated nitric acid/concentrated perchloric acid (4:1 v/v) is necessary.

 ^ Sample preparation includes addition of a polydithiocarbamate resin, filtration, ashing, and dissolution with concentrated nitric/concentrated perchloric acid (4:1 v/v).

 .Of the acid orthophosphates, the mono-calcium salt, CaH4(P04)2, may be obtained as crystalline scales, containing one molecule of water, by evaporating a solution of the normal salt in hydrochloric or nitric acid.^ Containers may explode when heated or contaminated with water.

 ^ In a heavily-watered mine it is often necessary to establish a special engine-pit, with pumps permanently fixed, or a division of one of the pits may be devoted to this purpose.

 ^ The metal is highly resistant to corrosion by many agents including concentrated nitric acid, 5% sulfuric acid, and sea water.
  • Titanium (EHC 24, 1982) 9 January 2010 0:56 UTC www.inchem.org [Source type: Academic]

 .It dissolves readily in water, the solution having an acid reaction.^ A supersaturated sugar solution contains more sugar than the water can dissolve at room temperature.

 ^ In this procedure, the oxides are converted, under heating, into water-soluble sulfates by fumes of sulfuric acid, after which the corresponding sulfates are identified by staining reactions.
  • Titanium (EHC 24, 1982) 9 January 2010 0:56 UTC www.inchem.org [Source type: Academic]

 ^ A sugar solution begins with sugar, partially dissolved in at least one-third its weight of cold water.

 .The artificial manure known as "superphosphate of lime" consists of this salt and calcium sulphate, and is obtained by treating ground bones, coprolites, &c., with sulphuric acid.^ To assess the value of calcium supplementation in preventing this loss of bone, the metabolic effects of administering 1 g of elemental calcium/day have been studied in 13 steroid-treated patients.

 The di-calcium salt, Ca2H2(P04)2, occurs in a concretionary form in the ureters and cloaca of the sturgeon, and also in guano. .It is obtained as rhombic plates by mixing dilute solutions of calcium chloride and sodium phosphate, and passing carbon dioxide into the liquid.^ The turbinado sugar is heated again to a liquid state, centrifuged, clarified with lime or phosphoric acid, and then percolated through a column of beef-bone char or mixed in a solution of activated carbon.

 ^ V7 766]**PEER REVIEWED** When heated in a dry carbon dioxide atmosphere, sodium cyanide fuses without much decomposition.

 ^ By increasing the molarity of the solutions, the binding to the resins of vitamin B12-intrinsic factor complex and of calcium chloride was completely inhibited.

 Other phosphates are also known.
.Calcium monosulphide, CaS, a white amorphous powder, sparingly soluble in water, is formed by heating the sulphate with charcoal, or by heating lime in a current of sulphuretted hydrogen.^ In this procedure, the oxides are converted, under heating, into water-soluble sulfates by fumes of sulfuric acid, after which the corresponding sulfates are identified by staining reactions.
  • Titanium (EHC 24, 1982) 9 January 2010 0:56 UTC www.inchem.org [Source type: Academic]

 ^ Titanium metal powder is usually produced by reaction of the metal with hydrogen; the resulting brittle titanium hydride is then crushed before heating in a vacuum to remove the hydrogen (Stamper, 1970).
  • Titanium (EHC 24, 1982) 9 January 2010 0:56 UTC www.inchem.org [Source type: Academic]

 ^ The resulting cyanide ion may then form hydrogen cyanide or react with various metals present in natural water.

 It is particularly noteworthy from the phosphorescence which it exhibits when heated, or after exposure to the sun's rays; hence its synonym "Canton's phosphorus," after John Canton (1718-1772), an English natural philosopher. The sulphydrate or hydrosulphide, Ca(SH)2, is obtained as colourless, prismatic crystals of the composition Ca(SH) 2.6H 2 O, by passing sulphuretted hydrogen into milk of lime. The strong aqueous solution deposits colourless, four-sided prisms of the hydroxy-hydrosulphide, Ca(OH) (SH). The disulphide, CaS2, and pentasulphide, CaS 5, are formed when milk of lime is boiled with flowers of sulphur. These sulphides form the basis of Balmain's luminous paint. An oxysulphide, 2CaS CaO, is sometimes present in "soda - waste," and orangecoloured, acicular crystals of 4CaS CaSO 4.18H 2 O occasionally settle out on the long standing of oxidized "sodaor alkali-waste" (see Alkali Manufacture).
.Calcium sulphite, CaSO 3, a white substance, soluble in water, is prepared by passing sulphur dioxide into milk of lime.^ It is then treated with sulphurous acid gas, for the purpose of decolorization, again limed to neutralize the acid, and then passed through a third saturator wherein all traces of lime and sulphur are removed.

 ^ In this procedure, the oxides are converted, under heating, into water-soluble sulfates by fumes of sulfuric acid, after which the corresponding sulfates are identified by staining reactions.
  • Titanium (EHC 24, 1982) 9 January 2010 0:56 UTC www.inchem.org [Source type: Academic]

 .This solution with excess of sulphur dioxide yields the "bisulphite of lime" of commerce, which is used in the "chemical" manufacture of woodpulp for paper making.^ A type of cell that makes neurohormones (chemicals that are made by nerve cells and used to send signals to other cells) and releases them into the blood.
  • Dictionary of Cancer Terms - National Cancer Institute 10 February 2010 12:52 UTC www.cancer.gov [Source type: Academic]

 ^ Use foam, dry chemical, or carbon dioxide.

 ^ Cream of lime of 17° Beaume is sometimes used, but the weaker solution is preferable, since the proper proportion is more easily adjusted.
Calcium sulphate, CaSO 4, constitutes the minerals anhydrite (q.v.), and, in the hydrated form, selenite, gypsum (q.v.), alabaster (q.v.), and also the adhesive plaster of Paris (see Cement). It occurs dissolved in most natural iwaters, which it renders "permanently hard." .It is obtained as a white crystalline precipitate, sparingly soluble in water (Loo parts of water dissolve 24 of the salt at 15° C.), by mixing solutions of a sulphate and a calcium salt; it is more soluble in solutions of common salt and hydrochloric acid, and especially of sodium thiosulphate.^ The ionized forms of calcium, such as citrate and citrate malate, tend to be more soluble and have a greater absorption rate, especially in people who are deficient in hydrochloric acid.

 ^ Cobalamin is water-soluble (can dissolve in water) and must be taken in every day.
  • Dictionary of Cancer Terms - National Cancer Institute 10 February 2010 12:52 UTC www.cancer.gov [Source type: Academic]

 ^ All sugars are colourless solids or syrups, which char on strong heating ; they are soluble in water, forming sweet solutions but difficultly soluble in alcohol .
Calcium silicates are exceptionally abundant in the mineral kingdom. .Calcium metasilicate, CaSiO 3, occurs in nature as monoclinic crystals known as tabular spar or wollastonite; it may be prepared artificially from solutions of calcium chloride and sodium silicate.^ The metallic characteristics of titanium are shown in compounds such as titanium chloride, phosphate, sulfate, and nitrate, whereas the non-metallic characteristics are exhibited in a series of titanates, e.g., calcium, iron, and sodium titanates.
  • Titanium (EHC 24, 1982) 9 January 2010 0:56 UTC www.inchem.org [Source type: Academic]

 ^ By increasing the molarity of the solutions, the binding to the resins of vitamin B12-intrinsic factor complex and of calcium chloride was completely inhibited.

 ^ PEER REVIEWED** Methods of Manufacturing: Sodium cyanide can be prepared by heating sodium amide with carbon, by melting sodium chloride and calcium cyanamide together in an electric furnace ...

 H. Le Chatelier (Annales des mines, 188 7, p. .345) has obtained artificially the compounds: CaSiO 3, Ca2S104, Ca3S1207, and Ca3S105. (See also G. Oddo, Chemisches Centralblatt, 1896, 228.) Acid calcium silicates are represented in the mineral kingdom by gyrolite, H2Ca2(S103)3 H20, a lime zeolite, sometimes regarded as an altered form of apophyllite, which is itself an acid calcium silicate containing an alkaline fluoride, by okenite, H2Ca(S103)2 H20, and by xonalite 4CaSiO 3 41 2 O. Calcium silicate is also present in the minerals: olivine, pyroxenes, amphiboles, epidote, felspars, zeolites, scapolites (qq.v.^ Calcium levoleucovorin is a form of folic acid.
  • Dictionary of Cancer Terms - National Cancer Institute 10 February 2010 12:52 UTC www.cancer.gov [Source type: Academic]

 ^ The risks of an adverse reaction between calcium citrate and aluminum-containing compounds are especially high for individuals with kidney failure, particularly those on dialysis.

 ^ OTHER SYRUPS Corn Syrup: Containing 24 percent water, corn syrup is obtained by partial hydrolysis of cornstarch by acid, alkaline or enzymatic catalysts.

 ).
.Detection and Estimation.-Most calcium compounds, especially when moistened with hydrochloric acid, impart an orange-red colour to a Bunsen flame, which when viewed through green glass appears to be finch-green; this distinguishes it in the presence of strontium, whose crimson coloration is apt to mask the orange-red calcium flame (when viewed through green glass the strontium flame appears to be a very faint yellow).^ Diagnostic tests: Moistened, after heating, with cobalt nitrate (CoNO 3 )and again ignited, a pink color is obtained from some infusible compounds of magnesium.
  • Mineral Species sorted by the element Mg Magnesium 16 January 2010 3:03 UTC webmineral.com [Source type: Reference]

 ^ The numerous cultivated varieties are distinguished mainly by the colour of the internodes, whether yellow, red or purple, or striped, and by the height.

 ^ The recall includes two types -- the green, yellow and orange-colored Carnotaurus (Model No.
  • Lead Paint Toy Recalls - Latest Lead Toy Recalls - Toxic Childrens Products - thedailygreen.com 14 January 2010 19:52 UTC www.thedailygreen.com [Source type: General]

 .In the spectroscope calcium exhibits two intense lines-an orange line (a), (X 6163), a green line (a), (X 4229), and a fainter indigo line.^ The recall includes two types -- the green, yellow and orange-colored Carnotaurus (Model No.
  • Lead Paint Toy Recalls - Latest Lead Toy Recalls - Toxic Childrens Products - thedailygreen.com 14 January 2010 19:52 UTC www.thedailygreen.com [Source type: General]

 Calcium is not precipitated by sulphuretted hydrogen, but falls as the carbonate when an alkaline carbonate is added to a solution. .Sulphuric acid gives a white precipitate of calcium sulphate with strong solutions; ammonium oxalate gives calcium oxalate, practically insoluble in water and dilute acetic acid, but readily soluble in nitric or hydrochloric acid.^ On warming the osazone with hydrochloric acid the phenylhydrazine residues are removed and an osone results, which on reduction with zinc and acetic acid gives a ketose.

 ^ The cyanide, as hydrocyanic acid, is released by refluxing the sample with strong acid and distillation of the hydrogen cyanide into an absorber-scrubber containing sodium hydroxide solution.

 ^ It is oxidized by nitric acid to d-saccharic and mucic acids; and acetic anhydride gives an octa-acetate.

 .Calcium is generally estimated by precipitation as oxalate which, after drying, is heated and weighed as carbonate or oxide, according to the degree and duration of the heating.^ V7 766]**PEER REVIEWED** When heated in a dry carbon dioxide atmosphere, sodium cyanide fuses without much decomposition.

 ^ PEER REVIEWED** Methods of Manufacturing: Sodium cyanide can be prepared by heating sodium amide with carbon, by melting sodium chloride and calcium cyanamide together in an electric furnace ...


Wiktionary

Up to date as of January 14, 2010

Definition from Wiktionary, a free dictionary

See also calcium

German

Chemical Element: Ca (atomic number 20)

Pronunciation

Noun

Calcium n
  1. calcium

Simple English

File:Calcium unter Argon Schutzgasatmosphä
Very pure calcium metal, not corroded

[[File:|thumb|Calcium metal in air, corroded]] Calcium is a chemical element. Its symbol on the periodic table (a list of all the elements) is Ca. Its atomic number is 20. (The atomic number says where Calcium sits in the periodic table.) It has 20 protons and 20 neutrons. Its mass number is about 40.08.

Contents

Properties

Physical properties

Calcium is a soft white-gray metal. It is an alkaline earth metal. It melts at a quite high temperature for a reactive metal. It is a little harder than lead. It has two allotropes. It does not conduct electricity as well as copper, but is much lighter.

Chemical properties

File:Calcium air 2.theora.ogv
Calcium metal burning

It reacts with water to produce hydrogen and calcium hydroxide. It reacts with water very fast when it is powdered. When it is in a chunk, it starts reacting slowly because calcium hydroxide makes a coating that does not dissolve on the calcium. If a little acid is added to calcium hydroxide, it dissolves it, making the calcium react very fast. It burns when powdered to make a reddish flame. This makes calcium oxide. It also makes calcium nitride when heated. It can react with halogens to make calcium halides like calcium chloride with chlorine.

Calcium compounds

Calcium forms chemical compounds in the +2 oxidation state. Calcium compounds are colorless. Most calcium compounds are not toxic. They are needed in the human body, actually. They are unreactive as far as calcium ions go. Calcium oxide was used to make limelights, which have a flame heating calcium oxide and makes it glow very bright.

Calcium

Calcium hydroxide

Calcium

Calcium chloride

Calcium sulfate

Calcium sulfate hydrated (with water)

Dusičnan vápenatý.JPG

Calcium nitrate

It is the 5th most common element on the earth.

Occurrence

In the ground

[[File:|thumb|Calcite]] Calcium is not found as a metal in the ground; it is too reactive. Calcium carbonate, also known as calcite, is the most common calcium mineral.

Calcium ions is very important for all organisms. To stay healthy it is important to eat calcium ions every day. Without enough calcium ions bones can become weak. This is called osteoporosis.

Calcium metal is not used in the human body; it will fizz and make toxic chemicals and flammable gases. Calcium compounds are used, like calcium carbonate or calcium phosphate.

Calcium in cells

It is important to know how cells work. Many cells have calcium channels on their surface. These are openings where calcium ions can enter the cell. The cell is told to act and it opens the channels. Once in the cell calcium ions activates many proteins to do specific things. For example, when it goes into muscle cells, it makes them contract (shorten so the muscle pulls.) When it goes into nerve cells, it triggers electrical impulses that send a messages. When it goes into white blood cells it makes them fight germs.

Calcium ions are important to cells and too many calcium ions can be bad. If a cell gets more calcium ion than it needs it can die. This is why the amount of calcium ion in cells is highly regulated. Conversely, not enough calcium ion is bad. Cells must have the right amount to function properly.

Sometimes cells are unhealthy and need to die in for the body to replace them with new, healthy cells. This keeps the whole organism healthy. Cells know when they should die and can trigger reactions to end their life cycles in many ways. When this happens it is called apoptosis, also known as a 'programmed cell death' (planned cell death.) One way cells accomplish apoptosis by taking in toxic levels of calcium ions.

Calcium storage

Bones contain most of the calcium ion in the human body. If we need more calcium for our blood, muscles, or other tissue, it comes from the bones. If we have extra calcium it goes into bones.

Calcium as an element is not found in the human body, just calcium ions in the form of chemical compounds.

Calcium regulation

Organisms need to keep calcium ion levels very well controlled. High calcium levels are bad, and low calcium levels are bad.

The body controls this by changing

  • how much calcium we get from the food we eat
  • how much calcium we lose in urine
  • how much calcium is put in bones

The control of calcium in the body is called calcium metabolism.

The body controls calcium levels with many hormones. Calcitonin, Parathyroid hormone (acronym PTH), and Vitamin D are the most important hormones in calcium metabolism. (Vitamin D is a hormone but it is called a vitamin.)

Preparation

Calcium metal is made by electrolysis of melted calcium chloride. It has to be very hot to melt it. The calcium metal is liquid.

Uses

As an element

Calcium is used in the reduction of other metals. It can also be used to make alloys with other metals.

As chemical compounds

File:Concrete pouring
Concrete used to make a building

Calcium compounds are also important in chemistry. It is important for making things. It is a part of cement which is needed to make concrete (a hard substance that many buildings are made from.)

Calcium is part of calcium oxide. Calcium oxide is used to make paper, pottery, food, and to purify water (make it good to drink.) Calcium carbonate is used as a calcium supplement. Calcium permanganate can be used as a rocket propellant.

Safety

Calcium is toxic as an element. It reacts with water and makes a strong base, calcium hydroxide. Calcium compounds are not toxic unless the anion is toxic. Calcium permanganate is only toxic because of the permanganate, not the calcium.

See also

frr:Kaltsium
Retrieved from "http://yak.rapint.com/wiki/Calcium"

Citable sentences

Up to date as of December 18, 2010

Here are sentences from other pages on Calcium, which are similar to those in the above article.








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