From Wikipedia, the free encyclopedia

Sodium oxide
IUPAC name	Sodium oxide
Other names	Disodium oxide
Identifiers
CAS number	1313-59-3 Y
PubChem	73971
UN number	1825
Properties
Molecular formula	Na2O
Molar mass	61.9789 g/mol
Appearance	White solid
Density	2.27 g/cm3
Melting point	1132°C
Boiling point	1950 °C decomposes
Solubility in water	reacts violently to form NaOH
Structure
Crystal structure	Antifluorite (face centered cubic), cF12
Space group	Fm3m, No. 225
Coordination geometry	Tetrahedral (Na+); cubic (O2–)
Thermochemistry
Std enthalpy of formation ΔfHo298	−414.2 kJ/mol
Standard molar entropy So298	75.1 J mol−1 K−1
Hazards
MSDS	ICSC 1653
EU Index	Not listed
Main hazards	Corrosive, reacts violently with water
Flash point	Non-flammable
Related compounds
Other anions	Sodium sulfide Sodium selenide Sodium telluride
Other cations	Lithium oxide Potassium oxide Rubidium oxide Caesium oxide
Related sodium oxides	Sodium peroxide Sodium superoxide
Related compounds	Sodium hydroxide
Y (what is this?)  (verify) Except where noted otherwise, data are given for materials in their standard state (at 25 °C, 100 kPa)
Infobox references

Sodium oxide (SOX) is a chemical compound with the formula Na₂O. It is used in ceramics and glasses. Treatment with water affords sodium hydroxide.

Na₂O + H₂O → 2 NaOH

The alkali metal oxides M₂O (M = Li, Na, K, Rb) crystallise in the antifluorite structure. In this motif the positions of the anions and cations are reversed relative to their positions in CaF₂, with sodium ions tetrahedrally coordinated to 4 oxide ions and oxide cubically coordinated to 8 sodium ions.^[1][2]

Applications

Glass making

In the typical application, glass contains around 15% sodium oxide, the other components being silica (silicon dioxide) and lime (calcium oxide) at around 70% and 9%, respectively. The soda serves as a flux to lower the temperature at which the silica melts. Soda glass has a lower melting temperature vs pure silica, and has improved mechanical properties due to its slight increases in elasticity. These changes arise because the silicon dioxide and soda react to form sodium silicates of the general formula Na₂[SiO₂]_x[SIO₃].

Other

Na₂O forms when sodium is treated with oxygen.

4 Na + O₂ → 2 Na₂O

Burning sodium in air will produce Na₂O and about 20% sodium peroxide Na₂O₂.

6 Na + 2 O₂ → 2 Na₂O + Na₂O₂

Pure Na₂O can be prepared by reaction of liquid sodium with NaNO₃.

10 Na + 2 NaNO₃ → 6 Na₂O + N₂

Sodium Oxide is also used in street lights and highway lights. They produce a yellow colored light.

References

External links

• Sodium oxide information at Webelements.
• External MSDS Data Sheet.