Cobalt(III) oxide
Chemical compound From Wikipedia, the free encyclopedia
Cobalt(III) oxide is the inorganic compound with the formula of Co2O3. Although only two oxides of cobalt are well characterized, CoO and Co3O4,[4] procedures claiming to give Co2O3 have been described. Thus treatment of Co(II) salts such as cobalt(II) sulfate with an aqueous solution of sodium hypochlorite (also known as bleach) gives a black solid:[5][6]
- 2CoSO4 + 4NaOH + NaOCl → Co2O3 + 2Na2SO4 + NaCl
_oxide.JPG) | |
| Names | |
|---|---|
| IUPAC name
cobalt(III) oxide, dicobalt trioxide | |
| Other names
cobaltic oxide, cobalt sesquioxide | |
| Identifiers | |
3D model (JSmol) |
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| ChemSpider | |
| ECHA InfoCard | 100.013.779 |
| EC Number |
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PubChem CID |
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| RTECS number |
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CompTox Dashboard (EPA) |
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| Properties | |
| Co2O3 | |
| Molar mass | 165.8646 g/mol |
| Appearance | red powder |
| Density | 5.18 g/cm3 [2] |
| Melting point | 895[3] °C (1,643 °F; 1,168 K) |
| negligible | |
| +4560.0·10−6 cm3/mol | |
| Structure | |
| Corundum, hR30 | |
| R3c, No. 167 | |
| Thermochemistry | |
Std enthalpy of formation (ΔfH⦵298) |
−577 kJ/mol |
| Hazards | |
| Occupational safety and health (OHS/OSH): | |
Main hazards |
toxic |
| GHS labelling: | |
  | |
| Warning | |
| H302, H317, H351, H410 | |
| P280 | |
| NFPA 704 (fire diamond) | |
Except where otherwise noted, data are given for materials in their standard state (at 25 °C [77 °F], 100 kPa).
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Some formulations of the catalyst hopcalite contain "Co2O3".
Some studies have been unable to synthesize the compound, and report that it is theoretically unstable.[7]
It is soluble in cold diluted sulfuric acid and produces Co2[SO4]3, which is blue in aqueous solution.
- Co2O3 + 3H2SO4 → Co2[SO4]3 + 3H2O
Cobalt(III) ion is a strong oxidizer in acidic solution, its standard electrode potential is +1.84V in this situation.[8]
See also
References
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