3D model (JSmol)
CompTox Dashboard (EPA)
|Molar mass||54.9886 g/mol|
|Appearance||Yellow to orange crystalline solid|
|Melting point||551.7 °C (1,025.1 °F; 824.9 K)|
Heat capacity (C)
|72.1 J/mol K|
|115.9 J/mol K|
Std enthalpy of
Gibbs free energy (ΔfG˚)
|P210, P220, P260, P280, P303+P361+P353, P305+P351+P338|
|NFPA 704 (fire diamond)|
|Flash point||Non flammable|
Except where otherwise noted, data are given for materials in their standard state (at 25 °C [77 °F], 100 kPa).
|what is ?)(|
Sodium superoxide is the inorganic compound with the formula NaO2. This yellow-orange solid is a salt of the superoxide anion. It is an intermediate in the oxidation of sodium by oxygen.
NaO2 is prepared by treating sodium peroxide with oxygen at high pressures:
It can also be prepared by careful oxygenation of a solution of sodium in ammonia:
It is also produced, along with sodium peroxide, when sodium is stored under inappropriate conditions (e.g. in dirty or partially halogenated solvents).
The product is paramagnetic, as expected for a salt of the O−
2 anion. It hydrolyses readily to give a mixture of sodium hydroxide, oxygen and hydrogen peroxide. It crystallizes in the NaCl motif.