Sodium superoxide is the inorganic compound with the formula NaO2.[1] This yellow-orange solid is a salt of the superoxide anion. It is an intermediate in the oxidation of sodium by oxygen.

Preparation

NaO2 is prepared by treating sodium peroxide with oxygen at high pressures:[2]

Na2O2 + O2 → 2 NaO2

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−
2 anion. It hydrolyses readily to give a mixture of sodium hydroxide, oxygen and hydrogen peroxide.[4] It crystallizes in the NaCl motif.

References

  1. ^ Hayyan, Maan; Hashim, Mohd Ali; AlNashef, Inas M. (2016-02-15). "Superoxide Ion: Generation and Chemical Implications". Chemical Reviews. 116 (5). American Chemical Society (ACS): 3029–3085. doi:10.1021/acs.chemrev.5b00407. ISSN 0009-2665. PMID 26875845.
  2. ^ Stephen E. Stephanou, Edgar J. Seyb Jr., Jacob Kleinberg "Sodium Superoxide" Inorganic Syntheses 1953; Vol. 4, 82-85.
  3. ^ Schechter, William H.; Sisler, Harry H.; Kleinberg, Jacob (January 1948). "The Absorption of Oxygen by Sodium in Liquid Ammonia: Evidence for the Existence of Sodium Superoxide". Journal of the American Chemical Society. 70 (1): 267–269. doi:10.1021/ja01181a083. ISSN 0002-7863.
  4. ^ Sasol Encyclopaedia of Science and Technology , G.C. Gerrans, P. Hartmann-Petersen , p.243 "sodium oxides" , google books link
Allikas: https://en.wikipedia.org/wiki/Sodium_superoxide
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