|Name, symbol, number||bismuth, Bi, 83|
|Element category||post-transition metal|
|Group, period, block||15, 6, p|
|Standard atomic weight||208.98040(1) g·mol−1|
|Electron configuration||[Xe] 4f14 5d10 6s2 6p3|
|Electrons per shell||2, 8, 18, 32, 18, 5 (Image)|
|Density (near r.t.)||9.78 g·cm−3|
|Liquid density at m.p.||10.05 g·cm−3|
|Melting point||544.7 K, 271.5 °C, 520.7 °F|
|Boiling point||1837 K, 1564 °C, 2847 °F|
|Heat of fusion||11.30 kJ·mol−1|
|Heat of vaporization||151 kJ·mol−1|
|Specific heat capacity||(25 °C) 25.52 J·mol−1·K−1|
|Oxidation states||3, 5
(mildly acidic oxide)
|Electronegativity||2.02 (Pauling scale)|
|1st: 703 kJ·mol−1|
|2nd: 1610 kJ·mol−1|
|3rd: 2466 kJ·mol−1|
|Atomic radius||156 pm|
|Covalent radius||148±4 pm|
|Van der Waals radius||207 pm|
|Electrical resistivity||(20 °C) 1.29x10^-6Ω·m|
|Thermal conductivity||(300 K) 7.97 W·m−1·K−1|
|Thermal expansion||(25 °C) 13.4 µm·m−1·K−1|
|Speed of sound (thin rod)||(20 °C) 1790 m/s|
|Young's modulus||32 GPa|
|Shear modulus||12 GPa|
|Bulk modulus||31 GPa|
|Brinell hardness||94.2 MPa|
|CAS registry number||7440-69-9|
|Most stable isotopes|
|Main article: Isotopes of bismuth|
Bismuth (pronounced /ˈbɪzməθ/, BIZ-məth) is a chemical element that has the symbol Bi and atomic number 83. This trivalent poor metal chemically resembles arsenic and antimony. Bismuth is heavy and brittle; it has a silvery white color with a pink tinge owing to the surface oxide. Bismuth is the most naturally diamagnetic of all metals, and only mercury has a lower thermal conductivity. It is generally considered to be the last naturally occurring stable, non-radioactive element on the periodic table, although it is actually slightly radioactive, with an extremely long half-life.
Bismuth compounds are used in cosmetics, medicines, and in medical procedures. As the toxicity of lead has become more apparent in recent years, alloy uses for bismuth metal as a replacement for lead have become an increasing part of bismuth's commercial importance.
Bismuth is a brittle metal with a white, silver-pink hue, often occurring in its native form with an iridescent oxide tarnish showing many refractive colors from yellow to blue. The spiral stair stepped structure of a bismuth crystal is the result of a higher growth rate around the outside edges than on the inside edges. The variations in the thickness of the oxide layer that forms on the surface of the crystal causes different wavelengths of light to interfere upon reflection, thus displaying a rainbow of colors. When combusted with oxygen, bismuth burns with a blue flame and its oxide forms yellow fumes. Its toxicity is much lower than that of its neighbors in the periodic table such as lead, tin, tellurium, antimony, and polonium.
Although ununpentium is theoretically more diamagnetic, no other metal is verified to be more naturally diamagnetic than bismuth. (Superdiamagnetism is a different physical phenomenon.) Of any metal, it has the second lowest thermal conductivity (after mercury) and the highest Hall coefficient. It has a high electrical resistance. When deposited in sufficiently thin layers on a substrate, bismuth is a semiconductor, rather than a poor metal.
Elemental bismuth is one of very few substances of which the liquid phase is denser than its solid phase (water being the best-known example). Bismuth expands 3.32% on solidification; therefore, it was long an important component of low-melting typesetting alloys, where it compensated for the contraction of the other alloying components.
Though virtually unseen in nature, high-purity bismuth can form distinctive hopper crystals. These colorful laboratory creations are typically sold to collectors. Bismuth is relatively nontoxic and has a low melting point just above 271 °C, so crystals may be grown using a household stove, although the resulting crystals will tend to be lower quality than lab-grown crystals.
While bismuth was traditionally regarded as the element with the heaviest stable isotope, bismuth-209, it had long been suspected to be unstable on theoretical grounds. This was finally demonstrated in 2003 when researchers at the Institut d'Astrophysique Spatiale in Orsay, France, measured the alpha emission half-life of 209Bi to be 1.9 × 1019 years, over a billion times longer than the current estimated age of the universe. Owing to its extraordinarily long half-life, for all presently-known medical and industrial applications bismuth can be treated as if it is stable and non-radioactive. The radioactivity is of academic interest, however, because bismuth is one of few elements whose radioactivity was suspected, and indeed theoretically predicted, before being detected in the laboratory.
Bismuth (New Latin bisemutum from German Wismuth, perhaps from weiße Masse, "white mass") was confused in early times with tin and lead because of its resemblance to those elements. Bismuth has been known since ancient times, and so no one person is credited with its discovery. Agricola, in De Natura Fossilium states that bismuth is a distinct metal in a family of metals including tin and lead in 1546 based on observation of the metals and their physical properties. Claude François Geoffroy demonstrated in 1753 that this metal is distinct from lead and tin.
"Artificial bismuth" was commonly used in place of the actual metal. It was made by hammering tin into thin plates, and cementing them by a mixture of white tartar, saltpeter, and arsenic, stratified in a crucible over an open fire.
In the Earth's crust, bismuth is about twice as abundant as gold. It is not usually economical to mine it as a primary product. Rather, it is usually produced as a byproduct of the processing of other metal ores, especially lead, tungsten (China), tin, copper, and also silver (indirectly) or other metallic elements.
The most important ores of bismuth are bismuthinite and bismite. In 2005, China was the top producer of bismuth with at least 40% of the world share followed by Mexico and Peru, reports the British Geological Survey. Native bismuth is known from Australia, Bolivia, and China.
According to the USGS, world 2006 bismuth mine production was 5,700 tonnes, of which China produced 3,000 tonnes, Mexico 1,180 tonnes, Peru 950 tonnes, and the balance Canada, Kazakhstan and other nations. World 2006 bismuth refinery production was 12,000 tonnes, of which China produced 8,500 tonnes, Mexico 1,180 tonnes, Belgium 800 tonnes, Peru 600 tonnes, Japan 510 tonnes, and the balance Canada and other nations.
The difference between world bismuth mine production and refinery production reflects bismuth's status as a byproduct metal. Bismuth travels in crude lead bullion (which can contain up to 10% bismuth) through several stages of refining, until it is removed by the Kroll-Betterton process or the Betts process. The Kroll-Betterton process uses a pyrometallurgical separation from molten lead of calcium-magnesium-bismuth drosses containing associated metals (silver, gold, zinc, some lead, copper, tellurium, and arsenic), which are removed by various fluxes and treatments to give high-purity bismuth metal (over 99% Bi). The Betts process takes cast anodes of lead bullion and electrolyzes them in a lead fluorosilicate-hydrofluorosilicic acid electrolyte to yield a pure lead cathode and an anode slime containing bismuth. Bismuth will behave similarly with another of its major metals, copper. Thus world bismuth production from refineries is a more complete and reliable statistic.
According to the Bismuth Advocate News, the price for bismuth metal from year-end 2000 to September 2005 was stuck in a range from $2.60 to $4.15 per lb., but after this period the price started rising rapidly as global bismuth demand as a lead replacement and other uses grew rapidly. New mines in Canada and Vietnam may relieve the shortages, but prices are likely to remain above their previous level for the foreseeable future. The Customer-Input price for bismuth is more oriented to the ultimate consumer; it started at US$39.40 per kilogram ($17.90 per pound) in January 2008 and reached US$35.55 per kg (US$16.15 per lb.) in September 2008.
While bismuth is most available today as a byproduct, its sustainability is more dependent on recycling. Bismuth is mostly a byproduct of lead smelting, along with silver, zinc, antimony, and other metals, and also of tungsten production, along with molybdenum and tin, and also of copper production. Recycling bismuth is difficult in many of its end uses, primarily because of scattering. Probably the easiest to recycle would be bismuth-containing fusible alloys in the form of larger objects, then larger soldered objects. Half of the world solder consumption is in electronics (i.e., circuit boards). As the soldered objects get smaller or contain little solder or little bismuth, the recovery gets progressively more difficult and less economic, although solder with a sizable silver content will be more worth recovering. Next in recycling feasibility would be sizeable catalysts with a fair bismuth content, perhaps as bismuth phosphomolybdate, and then bismuth used in galvanizing and as a free-machining metallurgical additive. Finally, the bismuth in the uses where it gets scattered the most, in stomach medicines (bismuth subsalicylate), paints (bismuth vanadate) on a dry surface, pearlescent cosmetics (bismuth oxychloride), and bismuth-containing bullets. The bismuth is so scattered in these uses as to be unrecoverable with present technology. Bismuth can also be available sustainably from greater efficiency of use or substitution, most likely stimulated by a rising price. For the stomach medicine, another active ingredient could be substituted for some or all of the bismuth compound. It would be more difficult to find an alternative to bismuth oxychloride in cosmetics to give the pearlescent effect. However, there are many alloying formulas for solders and therefore many alternatives.
The most important sustainability fact about bismuth is its byproduct status, which can either improve sustainability (i.e., vanadium or manganese nodules) or, for bismuth from lead ore, constrain it; bismuth is constrained. The extent that the constraint on bismuth can be ameliorated or not is going to be tested by the future of the lead storage battery, since 90% of the world market for lead is in storage batteries for gasoline or diesel-powered motor vehicles.
The life-cycle assessment of bismuth will focus on solders, one of the major uses of bismuth, and the one with the most complete information. The average primary energy use for solders is around 200 MJ per kg, with the high-bismuth solder (58% Bi) only 20% of that value, and three low-bismuth solders (2% to 5% Bi) running very close to the average. The global warming potential averaged 10 to 14 kg carbon dioxide, with the high-bismuth solder about two-thirds of that and the low-bismuth solders about average. The acidification potential for the solders is around 0.9 to 1.1 kg sulfur dioxide equivalent, with the high-bismuth solder and one low-bismuth solder only one-tenth of the average and the other low-bismuth solders about average. There is very little life-cycle information on other bismuth alloys or compounds.
Bismuth is stable to both dry and moist air at ordinary temperatures. At elevated temperatures, the vapours of the metal combine rapidly with oxygen, forming the yellow trioxide, Bi2O3. On reaction with base, this oxide forms two series of oxyanions: BiO −2, which is polymeric and forms linear chains, and BiO 3−3. The anion in Li3BiO3 is actually a cubic octameric anion, Bi8O 24−24, whereas the anion in Na3BiO3 is tetrameric.
Unlike earlier members of group 15 elements such as nitrogen, phosphorus, and arsenic, and similar to the previous group 15 element antimony, bismuth does not form a stable hydride analogous to ammonia and phosphine. Bismuth hydride, bismuthine (BiH3), is an endothermic compound that spontaneously decomposes at room temperature. It is stable only below −60°C.
The halides of bismuth in low oxidation states have been shown to have unusual structures. What was originally thought to be bismuth(I) chloride, BiCl, turns out to be a complex compound consisting of Bi 5+9 cations and BiCl 2−5 and Bi2Cl 2−8 anions. The Bi 5+9 cation is also found in Bi10HfCl18, prepared by reducing a mixture of hafnium(IV) chloride and bismuth chloride with elemental bismuth. Other polyatomic bismuth cations are also known, such as Bi 2+8, found in Bi8(AlCl4)2. Bismuth also forms a low-valence bromide with the same structure as "BiCl". There is a true monoiodide, BiI, which contains chains of Bi4I4 units. BiI decomposes upon heating to the triiodide, BiI3, and elemental bismuth. A monobromide of the same structure also exists.
In oxidation state +3, bismuth forms trihalides with all of the halogens: BiF3, BiCl3, BiBr3, and BiI3. All of these, except BiF3, are hydrolysed by water to form the bismuthyl cation, BiO+, a commonly encountered bismuth oxycation. Bismuth(III) chloride reacts with hydrogen chloride in ether solution to produce the acid HBiCl4.
Bismuth dissolves in nitric acid to form bismuth(III) nitrate, Bi(NO3)3. In the presence of excess water or the addition of a base, the Bi3+ ion reacts with the water to form BiO+, which precipitates as (BiO)NO3.
These mononuclear species are in equilibrium. Polynuclear species also exist, the most important of which is BiO+, which exists in hexameric form as the octahedral complex [Bi6O4(OH)4] 6+ (or 6 [BiO+]·2 H2O).
Bismuth oxychloride is sometimes used in cosmetics. Bismuth subnitrate and bismuth subcarbonate are used in medicine. Bismuth subsalicylate (the active ingredient in Pepto-Bismol and (modern) Kaopectate) is used as an antidiarrheal and to treat some other gastro-intestinal diseases (oligodynamic effect). Also, the product Bibrocathol is an organic molecule containing Bismuth and is used to treat eye infections. Bismuth subgallate (the active ingredient in Devrom) is used as an internal deodorant to treat malodor from flatulence (or gas) and faeces. Historically Bisthmuth compounds were used to treat Syphilis and today Bismuth subsalicylate and Bismuth subcitrate are used to treat the Peptic ulcer.
Some other current uses
In the early 1990s, research began to evaluate bismuth as a nontoxic replacement for lead in various applications:
According to the USGS, U.S. bismuth consumption in 2006 totaled 2,050 tonnes, of which chemicals (including pharmaceuticals, pigments, and cosmetics) were 510 tonnes, bismuth alloys 591 tonnes, metallurgical additives 923 tonnes, and the balance other uses.
Scientific literature concurs with the idea that bismuth and its compounds are less toxic than lead or its other periodic table neighbours (antimony, polonium) and that it isn't bioaccumulative. Its biological half-life for whole-body retention is 5 days but it can remain in the kidney for years in patients treated with bismuth compounds. In the industry, it is considered as one of the least toxic heavy metals.
Bismuth poisoning exists and mostly affects the kidney and liver. Skin and respiratory irritation can also follow exposure to respective organs. As with lead, overexposure to bismuth can result in the formation of a black deposit on the gingiva, known as a bismuth line.
Bismuth's environmental impacts are not very well known. It is considered that its environmental impact is small, due in part to the low solubility of its compounds. Limited information however means that a close eye should be kept on its impact.
BISMUTH, a metallic chemical element; symbol Bi, atomic weight 208.5 (0 = 16). It was probably unknown to the Greeks and Romans, but during the middle ages it became quite familiar, notwithstanding its frequent confusion with other metals. In 1450 Basil Valentine referred to it by the name "wismut," and characterized it as a metal; some years later Paracelsus termed it "wissmat," and, in allusion to its brittle nature, affirmed it to be a "bastard" or "half-metal"; Georgius Agricola used the form "wissmuth," latinized to "bisemutum," and also the term "plumbum cineareum." Its elementary nature was imperfectly understood; and the impure specimens obtained by the early chemists explain, in some measure, its confusion with tin, lead, antimony, zinc and other metals; in 1595 Andreas Libavius confused it with antimony, and in 1675 Nicolas Lemery with zinc. These obscurities began to be finally cleared up with the researches of Johann Heinrich Pott (1692-1777), a pupil of Stahl, published in his Exercitationes chemicae de Wismutho (1769), and of N. Geoffroy, son of Claude Joseph Geoffroy, whose contribution to our knowledge of this metal appeared in the Memoires de l'academie francaise for 1753. Torbern Olof Bergman reinvestigated its properties and determined its reactions; his account, which was published in his Opuscula, contains the first fairly accurate description of the metal.
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The principal source of bismuth is the native metal, which is occasionally met with as a mineral, usually in reticulated and arborescent shapes or as foliated and granular masses with a crystalline fracture. Although bismuth is readily obtained in fine crystals by artificial means, yet natural crystals are rare and usually indistinct: they belong to the rhombohedral system and a cube-like rhombohedron with interfacial angles of 92° 20' is the predominating form. There is a perfect cleavage perpendicular to the trigonal axis of the crystals: the fact that only two (opposite) corners of the cube-like crystals can be truncated by cleavage at once distinguishes them from true cubes. When not tarnished, the mineral has a silver-white colour with a tinge of red, and the lustre is metallic. Hardness 2-21; specific gravity 9-70-9.83. The slight variations in specific gravity are due to the presence of small amounts of arsenic, sulphur or tellurium, or to enclosed impurities.
Bismuth occurs in metalliferous veins traversing gneiss or clay-slate, and is usually associated with ores of silver and cobalt. Well-known localities are Schneeberg in Saxony and Joachimsthal in Bohemia; at the former it has been found as arborescent groups penetrating brown jasper, which material has occasionally been cut and polished for small ornaments. The mineral has been found in some Cornish mines and is fairly abundant in Bolivia (near Sorata, and at Tasna in Potosi). It is the chief commercial source of bismuth.
The oxide, bismuth ochre, Bi 2 O 3, and the sulphide, bismuth glance or bismuthite, are also of commercial importance. The former is found, generally mixed with iron, copper and arsenic oxides, in Bohemia, Siberia, Cornwall, France (Meymac) and other localities; it also occurs admixed with bismuth carbonate and hydrate. The hydrated carbonate, bismutite, is of less importance; it occurs in Cornwall, Bolivia, Arizona and elsewhere.
Of the rarer bismuth minerals we may notice the following: - the complex sulphides, copper bismuth glance or wittichenite, BiCu 3 S 3, silver bismuth glance, bismuth cobalt pyrites, bismuth nickel pyrites or saynite, needle ore (patrinite or aikinite), BiCuPbS 3, emplectite, CuBiS 2, and kobellite, BiAsPb 3 S 6; the sulphotelluride tetradymite; the selenide guanajuatite, B12Se3, Iv. I a the basic tellurate montanite, Bi 2 (OH) 4 TeO 4; the silicates eulytite and agricolite, B14(S104) 3; and the uranyl arsenate walpurgite, Bi(U02)3(OH)24(As04)4.
Bismuth is extracted from its ores by dry, wet, or electro-metallurgical methods, the choice depending upon the composition of the ore and economic conditions. The dry process is more frequently practised, for the easy reducibility of the oxide and sulphide, together with the low melting-point of the metal, renders it possible to effect a ready separation of the metal from the gangue and impurities. The extraction from ores in which the bismuth is present in the metallic condition may be accomplished by a simple liquation, or melting, in which the temperature is just sufficient to melt the bismuth, or by a complete fusion of the ore. The first process never extracts all the bismuth, as much as onethird being retained in the matte or speiss; the second is more satisfactory, since the extraction is more complete, and also allows the addition of reducing agents to decompose any admixed bismuth oxide or sulphide. In the liquation process the ore is heated in inclined cylindrical retorts, and the molten metal is tapped at the lower end; the residues being removed from the upper end. The fusion process is preferably carried out in crucible furnaces; shaft furnaces are unsatisfactory on account of the disintegrating action of the molten bismuth on the furnace linings.
Sulphuretted ores are smelted, either with or without a preliminary calcination, with metallic iron; calcined ores may be smelted with carbon (coal). The reactions are strictly analogous to those which occur in the smelting of galena (see Lead), the carbon reducing any oxide, either present originally in the ore or produced in the calcination, and the iron combining with the sulphur of the bismuthite. A certain amount of bismuth sulphate is always formed during the calcination; this is subsequently reduced to the sulphide and ultimately to the metal in the fusion. Calcination in reverberatory furnaces and a subsequent smelting in the same type of furnace with the addition of about 3% of coal, lime, soda and fluorspar, has been adopted for treating the Bolivian ores, which generally contain the sulphides of bismuth, copper, iron, antimony, lead and a little silver. The lowest layer of the molten mass is principally metallic bismuth, the succeeding layers are a bismuth copper matte, which is subsequently worked up, and a slag. Ores containing the oxide and carbonate are treated either by smelting with carbon or by a wet process.
In the wet process the ores, in which the bismuth is present as oxide or carbonate, are dissolved out with hydrochloric acid, or, if the bismuth is to be extracted from a matte or alloy, the solvent employed is aqua regia or strong sulphuric acid. The solution of metallic chlorides or sulphates so obtained is precipitated by iron, the metallic bismuth filtered, washed with water, pressed in canvas bags, and finally fused in graphite crucibles, the surface being protected by a layer of charcoal. Another process consists in adding water to the solution and so precipitating the bismuth as oxychloride, which is then converted into the metal.
The crude metal obtained by the preceding processes is generally contaminated by arsenic, sulphur, iron, nickel, cobalt and antimony, and sometimes with silver or gold. A dry method of purification consists in a liquation on a hearth of peculiar construction, which occasions the separation of the unreduced bismuth sulphide and the bulk of the other impurities. A better process is to remelt the metal in crucibles with the addition of certain refining agents. The details of this process vary very considerably, being conditioned by the composition of the impure metal and the practice of particular works. The wet refining process is more tedious and expensive, and is only exceptionally employed, as in the case of preparing the pure metal or its salts for pharmaceutical or chemical purposes. The basic nitrate is the salt generally prepared, and, in general outline, the process consists in dissolving the metal in nitric acid, adding water to the solution, boiling the precipitated basic nitrate with an alkali to remove the arsenic and lead, dissolving the residue in nitric acid, and reprecipitating as basic nitrate with water. J. F. W. Hampe prepared chemically pure bismuth by fusing the metal with sodium carbonate and sulphur, dissolving the bismuth sulphide so formed in nitric acid, precipitating the bismuth as the basic nitrate, redissolving this salt in nitric acid, and then precipitating with ammonia. The bismuth hydroxide so obtained is finally reduced by hydrogen.
Bismuth is a very brittle metal with a white crystalline fracture and a characteristic reddish-white colour. It crystallizes in rhombohedra belonging to the hexagonal system, having interfacial angles of 87° 40'. According to G. W. A. Kahlbaum, Roth and Siedler (Zeit. Anorg. Chem. 2 9, p. 2 94), its specific gravity is 9.7 81 43; Roberts and Wrightson give the specific gravity of solid bismuth as 9.82, and of molten bismuth as to 055. It therefore expands on solidification; and as it retains this property in a number of alloys, the metal receives extensive application in forming type-metals. Its melting-point is variously given as 268.3° (F. Rudberg and A. D. von Riemsdijk) and 270.5° (C. C. Person); commercial bismuth melts at 260° (Ledebur), and electrolytic bismuth at 264° (Classen). It vaporizes in a vacuum at 292°, and its boiling-point, under atmospheric pressure, is between 1090° and 1450° (T. Carnelley and W. C. Williams). Regnault determined its specific heat between o° and too° to be 0.0308; Kahlbaum, Roth and Siedler (loc. cit.) give the value 0.03055. Its thermal conductivity is the lowest of all metals, being 18 as compared with silver as 1000; its coefficient of expansion between o° and too° is 0.001341. Its electrical conductivity is approximately 1.2, silver at 0° being taken as 100; it is the most diamagnetic substance known, and its thermoelectric properties render it especially valuable for the construction of thermopiles.
The metal oxidizes very slowly in dry air at ordinary temperatures, but somewhat more rapidly in moist air or when heated. In the last case it becomes coated with a greyish-black layer of an oxide (dioxide (?)), at a red heat the layer consists of the trioxide (B1203), and is yellow or green in the case of pure bismuth, and violet or blue if impure; at a bright red heat it burns with a bluish flame to the trioxide. Bismuth combines directly with the halogens, and the elements of the sulphur group. It readily dissolves in nitric acid, aqua regia, and hot sulphuric acid, but tardily in hot hydrochloric acid. It is precipitated as the metal from solutions of its salts by the metals of the alkalis and alkaline earths, zinc, iron, copper, &c. In its chemical affinities it resembles arsenic and antimony; an important distinction is that it forms no hydrogen compound analogous to arsine and stibine.
Bismuth readily forms alloys with other metals. Treated with sodammonium it yields a bluish-black mass, BiNa 3, which takes fire in the air and decomposes water. A brittle potassium alloy of silver-white colour and lamellar fracture is obtained by calcining 20 parts of bismuth with 16 of cream of tartar at a strong red heat. When present in other metals, even in very small quantity, bismuth renders them brittle and impairs their electrical conductivity. With mercury it forms amalgams. Bismuth is a component of many ternary alloys characterized by their low fusibility and expansion in solidification; many of them are used in the arts (see Fusible Metal).
Bismuth forms four oxides, of which the trioxide, B1203, is the most important. This compound occurs in nature as bismuth ochre, and may be prepared artificially by oxidizing the metal at a red heat, or by heating the carbonate, nitrate or hydrate. Thus obtained it is a yellow powder, soluble in the mineral acids to form soluble salts, which are readily precipitated as basic salts when the solution is diluted. It melts to a reddish-brown liquid, which solidifies to a yellow crystalline mass on cooling. The hydrate, Bi(OH) 3 i is obtained as a white powder by adding potash to a solution of a bismuth salt. Bismuth dioxide, BiO or Bi 2 O 2, is said to be formed by the limited oxidation of the metal, and as a brown precipitate by adding mixed solutions of bismuth and stannous chlorides to a solution of caustic potash. Bismuth tetroxide, Bi 2 O 4, sometimes termed bismuth bismuthate, is obtained by melting bismuth trioxide with potash, or by igniting bismuth trioxide with potash and potassium chlorate. It is also formed by oxidizing bismuth trioxide suspended in caustic potash with chlorine, the pentoxide being formed simultaneously; oxidation and potassium ferricyanide simply gives the tetroxide (Hauser and Vanino, Zeit. Anorg. Chem., 1904, 39, p.38t). The hydrate, B1204.2H20, is also known. Bismuth pentoxide, B12C,, is obtained by heating bismuthic acid, HBiO 3, to 130° C.; this acid (in the form of its salts) being the product of the continued oxidation of an alkaline solution of bismuth trioxide.
Bismuth forms two chlorides: BiC1 2 and BiC1 3. The dichloride, BiC1 2, is obtained as a brown crystalline powder by fusing the metal with the trichloride, or in a current of chlorine, or by heating the metal with calomel to 250°. Water decomposes it to metallic bismuth and the oxychloride, BiOC1. Bismuth trichloride, BiC13, was obtained by Robert Boyle by heating the metal with corrosive sublimate. It is the final product of burning bismuth in an excess of chlorine. It is a white substance, melting at 225 0 -230° and boiling at 435 °-44 1 °. With excess of water, it gives a white precipitate of the oxychloride, BiOC1. Bismuth trichloride forms double compounds with hydrochloric acid, the chlorides of the alkaline metals, ammonia, nitric oxide and nitrosyl chloride. Bismuth trifluoride, BiF3, a white powder, bismuth tribromide, BiBr 3, golden yellow crystals, bismuth iodide, Bi13, greyish-black crystals, are also known. These compounds closely resemble the trichloride in their methods of preparation and their properties, forming oxyhaloids with water, and double compounds with ammonia, &c.
The basic carbonate, 2(B10) 2 CO 3 4H 2 O, obtained as a white precipitate when an alkaline carbonate is added to a solution of bismuth nitrate, is employed in medicine. Another basic carbonate, 3(BiO) 2 CO 3.2Bi(OH)3.3H20, constitutes the mineral bismutite.
The normal nitrate, Bi(N03)3.5H20, is obtained in large transparent asymmetric prisms by evaporating a solution of the metal in nitric acid. The action of water on this solution produces a crystalline precipitate of basic nitrate, probably Bi(OH)2N03, though it varies with the amount of water employed. This precipitate constitutes the "magistery of bismuth" or "subnitrate of bismuth" of pharmacy, and under the name of pearl white, blanc d'Espagne or blanc de fard has long been used as a cosmetic.
Bismuth combines directly with sulphur to form a disulphide, B12S2, and a trisulphide, B12S3, the latter compound being formed when the sulphur is in excess. A hydrated disulphide, B12S2.2H20, is obtained by passing sulphuretted hydrogen into a solution of bismuth nitrate and stannous chloride. Bismuth disulphide is a grey metallic substance, which is decomposed by hydrochloric acid with the separation of metallic bismuth and the formation of bismuth trichloride. Bismuth trisulphide, B12S3, constitutes the mineral bismuthite, and may be prepared by direct union of its constituents, or as a brown precipitate by passing sulphuretted hydrogen into a solution of a bismuth salt. It is easily soluble in nitric acid. When heated to 200 0 it assumes the crystalline form of bismuthite. Bismuth forms several oxysulphides: Bi 4 O,S constitutes the mineral karelinite found at the Zavodinski mine in the Altai; B1603S4 and Bi 2 OsS have been prepared artificially. Bismuth also forms the sulphohaloids, BiSCI, BiSBr, BiSI, analogous to the oxyhaloids.
Bismuth sulphate, B12(S04)3, is obtained as a white powder by dissolving the metal or sulphide in concentrated sulphuric acid. Water decomposes it, giving a basic salt, Bi 2 (SO 4)(OH) i which on heating gives (BiO) 2 SO 4. Other basic salts are known.
Bismuth forms compounds similar to the trisulphide with the elements selenium and tellurium. The tritelluride constitutes the mineral tetradymite, B12Te3.
Traces of bismuth may be detected by treating the solution with excess of tartaric acid, potash and stannous chloride, a precipitate or dark coloration of bismuth oxide being formed even when only one part of bismuth is present in 20,000 of water. The blackish brown sulphide precipitated from bismuth salts by sulphuretted hydrogen is insoluble in ammonium sulphide, but is readily dissolved by nitric acid. The metal can be reduced by magnesium, zinc, cadmium, iron, tin, copper and substances like hypophosphorous acid from acid solutions or from alkaline ones by formaldehyde. In quantitative estimations it is generally weighed as oxide, after precipitation as sulphide or carbonate, or in the metallic form, reduced as above.
The salts of bismuth are feebly antiseptic. Taken internally the subnitrate, coming into contact with water, tends to decompose, gradually liberating nitric acid, one of the most powerful antiseptics. The physical properties of the powder also give it a mild astringent action. There are no remote actions.
The subnitrate of bismuth is invaluable in certain cases of dyspepsia, and still more notably so in diarrhoea. It owes its value to the decomposition described above, by means of which a powerful antiseptic action is safely and continuously exerted. 'There is hardly a safer drug. It may be given in drachm doses with impunity. It colours the faeces black owing to the formation of sulphide.
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For etymology and more information refer to: http://elements.vanderkrogt.net/elem/bi.html (A lot of the translations were taken from that site with permission from the author)
bismuth m (usually uncountable)
[[File:|thumb|Bismuth]] Bismuth is a chemical element. It is element 83 on the periodic table and its symbol is Bi. Its atomic mass is 209. It is only a very little radioactive. The radioactivity is so little that it is seen as nonradioactive normally. Bismuth is only found as one isotope naturally, which is the almost nonradioactive one. Its radioactivity was predicted by scientists and proven by analyzing the metal. It is in Group 15 on the periodic table.
[[File:|thumb|Bismuth crystals can have a thin layer of bismuth(III) oxide on the outside that is very colorful.]] Bismuth is a silver metal with a pink tinge to it. This pink color is because of its oxide coating. Bismuth is a post-transition metal. It is one of the strongest diamagnetic metals. It is almost as heavy as lead. Its melting point is quite low
Bismuth is somewhat similar to antimony. Bismuth makes a thin coating of bismuth(III) oxide when it is in air. This makes the colors on the crystals. It does not oxidize any more than the oxide layer. It burns when powdered with a bright blue flame, making yellow bismuth(III) oxide fumes. Bismuth reacts with sulfur when molten as well. Bismuth reacts with nitric acid to make bismuth(III) nitrate and concentrated sulfuric acid to make bismuth(III) sulfate and sulfur dioxide. It reacts with the halogens to make bismuth(III) halides. With fluorine it makes bismuth(V) fluoride unless the fluorine is diluted, though.
Bismuth forms chemical compounds in two main oxidation states: +3 and +5. +3 is the most common. +3 compounds are weak oxidizing agents and are normally light yellow. +5 compounds are strong oxidizing agents. Bismuthates are the most common +5 compounds. Bismuth(V) fluoride is another +5 compound. Bismuth(V) oxide is an unstable red solid. Bismuth sulfide is a common ore of bismuth. Bismuthine, a bismuth hydride, is very unstable and only can be made at very cold temperatures. Bismuth makes many oxy- compounds like bismuth oxychloride. These compounds are made when bismuth halides dissolve in water.
Bismuth was known since ancient times. It was confused with tin and lead, though. No one is credited for discovering bismuth. In the 1500's people started realizing that bismuth was different than tin or lead.
Bismuth is not very common in the earth. It is only about twice as common as gold. Bismite, a bismuth oxide mineral, and bismuthinite, a bismuth sulfide, are two common ores. Bismuth is sometimes found as a metal, too.
Bismuth and its minerals are too rare to be mined. They are gotten by "secondary extraction". It is normally found in lead metal. The lead metal is purified by electrolysis, leaving the bismuth behind as a sludge on the bottom of the container. The copper is taken out of the sludge and the bismuth is purified by being reduced in a furnace and all the impurities are filtered out.
Bismuth can also be recycled. This is difficult in many places because bismuth is used for things like bullets, solder, and stomach medicine that get scattered all over and cannot easily be gotten again.
Bismuth is used in alloys with very low melting points. Some of them melt in hot water. They are also found in solder that does not have lead in it. It can make alloys with other metals to make them more malleable. It is also used in bullets to replace lead. In some places lead bullets are outlawed as birds eat them and get lead poisoning. It is also used in alloys for plumbing. It is used in fishing sinkers.
Bismuth oxychloride is used in cosmetics. Bismuth telluride is used in electronic thermometers. Another compound is used in superconductors and becomes a superconductor at a high temperature. It can be used as a pigment and in fireworks to make crackling sounds. It is used in the nuclear fuel of a nuclear reactor.
Bismuth is much less toxic than other heavy metals. This is why it is replacing lead in many things. It does not add up in the body like other heavy metals do. A very large amount of bismuth can poison the kidneys and liver, though. Because its oxide does not dissolve in water, it is considered safe for the environment.