Sodium oxide

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Sodium oxide

General
Systematic name	Sodium oxide
Other names	Disodium oxide, soda
Molecular formula	Na₂O
Molar mass	61.979
Appearance	White solid
CAS number	[1313-59-3]
Properties
Density and phase	2.270 g/cm³
Solubility in water	Decomposes
Other solvents	Insolubility
Melting point	1132 °C
Boiling point	Decomposes at 1950 °C
Structure
Coordination geometry	8-coordinate
Crystal structure	cubic
Hazards
MSDS	External MSDS
EU classification	Corrosive (C)
R-phrases	R8, R14, R35
S-phrases	S8, S27, S39, S43, S45
NFPA 704	0 3 1
Flash point	Non-flammable
Supplementary data page
Structure and properties	n, ε_r, etc.
Thermodynamic data	Phase behaviour Solid, liquid, gas
Spectral data	UV, IR, NMR, MS
Except where noted otherwise, data are given for materials in their standard state (at 25 °C, 100 kPa) Infobox disclaimer and references

Sodium oxide is a chemical compound with the formula Na₂O. It is used in ceramics and glasses. Like most metal oxides, Na₂O can exists only as the pure material - it cannot be dissolved in any solvent without reacting irreversibly. For example, treatment with water affords sodium hydroxide.

Na₂O + H₂O → 2 NaOH

The alkali metal oxides M₂O (M = 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.^[1]

1 Applications
2 See also
3 References
4 External links

[edit] Applications

Typically, glass contains around 15% sodium oxide, the other components being silicon dioxide and 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 the its slightly increases elasticity. These changes arise because the silicon dioxide and soda react to form sodium silicates of the general formula Na₂[SiO₂]_x[SiO₃].

Na₂O forms when sodium is treated with oxygen.

4 Na + O₂ → 2 Na₂O