Sodium superoxide
| Names | |
|---|---|
| IUPAC name
sodium(I) superoxide | |
| Other names
sodium superoxide | |
| Identifiers | |
12034-12-7  | |
| 3D model (Jmol) | Interactive image |
| PubChem | 61542 |
| RTECS number | WE2860010 |
| |
| |
| 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 | |
| 72.1 J/mol K | |
| Std molar entropy (S |
115.9 J/mol K |
| Std enthalpy of formation (ΔfH |
-260.2 kJ/mol |
| Gibbs free energy (ΔfG˚) |
-218.4 kJ/mol |
| Hazards | |
| EU classification (DSD) |
Corrosive |
| R-phrases | R35 |
| S-phrases | S1/2, S26, S37/39, S45 |
| NFPA 704 | |
| Flash point | Non flammable |
| Related compounds | |
| Other anions |
sodium oxide sodium peroxide |
| Other cations |
potassium superoxide |
| Except where otherwise noted, data are given for materials in their standard state (at 25 °C [77 °F], 100 kPa). | |
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| 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
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
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