Potassium superoxide
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| Potassium superoxide | |
|---|---|
| Image:Potassium superoxide.jpg | |
| General | |
| Systematic name | Potassium dioxide |
| Other names | Potassium superoxide |
| Molecular formula | KO2 |
| Molar mass | 71.10 g/mol |
| Appearance | yellow solid |
| CAS number | [12030-88-5] |
| Properties | |
| Density and phase | 2.14 g/cm3, solid |
| Solubility in water | Decomposes |
| Melting point | 425 °C decomp. |
| Structure | |
| Coordination geometry |
? |
| Crystal structure | ? |
| Hazards | |
| MSDS | External MSDS |
| Main hazards | corrosive |
| NFPA 704 |    |
| R/S statement | R: 8-14-34 S: 17-27-36/37/39 |
| Supplementary data page | |
| Structure and properties |
n, εr, etc. |
| Thermodynamic data |
Phase behaviour Solid, liquid, gas |
| Spectral data | UV, IR, NMR, MS |
| Related compounds | |
| Other anions | Potassium oxide Potassium peroxide |
| Other cations | Sodium superoxide |
| Except where noted otherwise, data are given for materials in their standard state (at 25 °C, 100 kPa) Infobox disclaimer and references |
|
Potassium superoxide is the chemical compound with the formula KO2. This rare salt of the superoxide ion is produced by burning molten potassium in pure oxygen. Potassium superoxide is used as an oxidizing agent in industrial chemistry, as a CO2 scrubber, H2O dehumidifier and O2 generator in rebreathers, spacecraft and spacesuit life support systems.
Important reactions:
- 4 KO2 + 2 H2O → 4 KOH + 3 O2
- 2 KOH + CO2 → K2CO3 + H2O
- K2CO3 + CO2 + H2O → 2 KHCO3
The Russian Space Agency has had success using potassium superoxide in chemical oxygen generators for its spacesuits and Soyuz spacecraft. KO2 has also been utilized in canisters for rebreathers for fire fighting and mine rescue work, but had limited use in scuba rebreathers because of the dangers of explosive reaction with water. The theoretical capacity of KO2 is the absorption of 0.309 kg CO2 per kg of absorbent while 0.38 kg O2 are generated per kg of absorbent. The human body though will produce more CO2 than oxygen absorbed, thus a device or absorbent specifically for CO2 scrubbing may also be required.
[edit] Structural trends in dioxygen compounds
The derivatives of dioxygen, O2, have characteristic O-O distances that correlate with the bond order of the O-O bond.
| Dioxygen compound | name | O-O distance in Å | O-O bond order |
|---|---|---|---|
| O2+ | dioxygenyl cation | 1.12 | 2.5 |
| O2 | dioxygen | 1.21 | 2 |
| O2- | superoxide | 1.28 | 1.5[1] |
| O22- | peroxide | 1.49 | 1 |
[edit] References
- ^ Abrahams, S. C.; Kalnajs, J. “The Crystal Structure of α-Potassium Superoxide” Acta Crystallographica (1955) volume 8, pages 503-506. DOI:10.1107/S0365110X55001540.
[edit] External links
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