Sodium superoxide is the inorganic compound with the formulaNaO2.[1] This yellow-orange solid is a salt of the superoxide anion. It is an intermediate in the oxidation of sodium by oxygen.
It can also be prepared by careful oxygenation of a solution of sodium in cryogenic liquid ammonia:
Na(in NH3) + O2 → NaO2
Although the existence of a sodium oxide higher than peroxide was speculated since 19th century, it was not until 1948 when American chemists were able to definitely synthesize it by the latter method.[3]
It is also produced, along with sodium peroxide, when sodium is stored under inappropriate conditions (e.g. in dirty or partially halogenated solvents)[citation needed].
Properties
The product is paramagnetic, as expected for a salt of the O− 2anion. It hydrolyses readily to give a mixture of sodium hydroxide, oxygen and hydrogen peroxide.[4] It crystallizes in the NaCl motif.
