Sodium superoxide
Names | |
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IUPAC name
sodium(I) superoxide
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Other names
sodium superoxide
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Identifiers | |
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PubChem CID
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RTECS number |
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CompTox Dashboard (EPA)
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Properties | |
NaO2 | |
Molar mass | 54.9886 g/mol |
Appearance | Yellow to orange crystalline solid |
Density | 2.2 g/cm3 |
Melting point | 551.7 °C (1,025.1 °F; 824.9 K) |
Boiling point | Decomposes |
Decomposes | |
Basicity (pKb) | N/A |
Structure | |
cubic | |
Thermochemistry | |
Heat capacity (C)
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72.1 J/mol K |
Std molar
entropy (S |
115.9 J/mol K |
Std enthalpy of
formation (ΔfH⦵298) |
-260.2 kJ/mol |
Gibbs free energy (ΔfG˚)
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-218.4 kJ/mol |
Hazards | |
EU classification (DSD) (outdated)
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Corrosive |
R-phrases (outdated) | R35 |
S-phrases (outdated) | S1/2, S26, S37/39, S45 |
NFPA 704 (fire diamond) |
3
0
1 OX |
Flash point | Non flammable |
Related compounds | |
Other anions
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sodium oxide sodium peroxide |
Other cations
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Lithium superoxide Potassium superoxide Rubidium superoxide |
Except where otherwise noted, data are given for materials in their standard state (at 25 °C [77 °F], 100 kPa). | |
what is ?) | (|
Infobox references | |
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 ammonia:
- Na(in NH3) + O2 → NaO2
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.[3] It crystallizes in the NaCl motif.
References[]
- ^ Hayyan M., Hashim M.A., AlNashef I.M., Superoxide Ion: Generation and Chemical Implications, Chem. Rev., 2016, 116 (5), pp 3029–3085. DOI: 10.1021/acs.chemrev.5b00407
- ^ Stephen E. Stephanou, Edgar J. Seyb Jr., Jacob Kleinberg "Sodium Superoxide" Inorganic Syntheses 1953; Vol. 4, 82-85.
- ^ Sasol Encyclopaedia of Science and Technology , G.C. Gerrans, P. Hartmann-Petersen , p.243 "sodium oxides" , google books link
Categories:
- Superoxides
- Sodium compounds
- Photographic chemicals
- Oxidizing agents
- Inorganic compound stubs