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 M
2O (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.
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 Na
2[SiO
2]
x[SIO
3].
Other
Na
2O forms when sodium is treated with
oxygen.
4 Na + O2 → 2 Na2O
Burning sodium in
air will produce Na
2O and about 20%
sodium peroxide Na
2O
2.
6 Na + 2 O2 → 2 Na2O + Na2O2
Pure Na
2O can be prepared by reaction of liquid
sodium with
NaNO3.
10 Na + 2 NaNO
3 → 6 Na
2O +
N2Sodium Oxide is also used in
street lights and highway lights. Owners of
highways and
streets have been asked to use Na
2O lights because of their high brightness.
