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Names | |
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IUPAC name
sodium superoxide
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Other names
sodium superoxide
sodium dioxide | |
Identifiers | |
3D model (JSmol)
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ChemSpider | |
PubChem CID
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RTECS number |
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UNII | |
UN number | 2547 |
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/cm |
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 (S298) |
115.9 J/mol K |
Std enthalpy of
formation (ΔfH298) |
-260.2 kJ/mol |
Gibbs free energy (ΔfG)
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-218.4 kJ/mol |
Hazards | |
GHS labelling: | |
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Danger | |
H271, H314 | |
P210, P220, P260, P280, P303+P361+P353, P305+P351+P338 | |
NFPA 704 (fire diamond) | |
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 Caesium superoxide |
Except where otherwise noted, data are given for materials in their standard state (at 25 °C ※, 100 kPa).
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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.
Preparation※
NaO2 is prepared by treating sodium peroxide with oxygen at high pressures:
- 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).
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. It crystallizes in the NaCl motif.
References※
- ^ 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.
- ^ 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