Cobalt(II,III) oxide
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| Names | |
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| IUPAC name
cobalt(II) dicobalt(III) oxide | |
Other names
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| Identifiers | |
3D model (JSmol) |
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| ChemSpider | |
| ECHA InfoCard | 100.013.780 |
| EC Number |
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PubChem CID |
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| RTECS number |
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| UNII | |
CompTox Dashboard (EPA) |
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| Properties | |
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| Molar mass | 240.796 g·mol−1 |
| Appearance | black solid |
| Density | 6.07 g/cm3[2] |
| Melting point | 895 °C (1,643 °F; 1,168 K) |
| Boiling point | 900 °C (1,650 °F; 1,170 K) (decomposes) |
| Insoluble | |
| Solubility | soluble (with degradation) in acids and alkalis |
| 7380×10−6 cm3/mol | |
| Structure | |
| cubic | |
| Fd3m, No. 227[3] | |
| Hazards | |
| GHS labelling:[citation needed] | |
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| Danger | |
| H317, H334, H350, H411 | |
| P261, P273, P284, P304+P340, P342+P311 | |
| 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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Cobalt(II,III) oxide is an inorganic compound with the formula Co3O4. Along with cobalt(II) oxide, it is one of two well characterized and stable cobalt oxides.[4] It is a black antiferromagnetic solid. As a mixed valence compound, its formula is sometimes written as Co2+Co3+2O4 and sometimes as CoO·Co2O3.[5] It occurs naturally as the rare mineral guite which is named in honor of Prof. Xiangping Gu (1964-).[6]
Structure
[edit]Co3O4 adopts the normal spinel structure, with Co2+ ions in tetrahedral interstices and Co3+ ions in the octahedral interstices of the cubic close-packed lattice of oxide anions.[5]
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| tetrahedral coordination geometry of Co(II) | distorted octahedral coordination geometry of Co(III) | distorted tetrahedral coordination geometry of O |
Synthesis
[edit]Cobalt(II) oxide, CoO, converts to Co3O4 upon heating at around 600–700 °C (1,112–1,292 °F) in air.[5] Above 900 °C (1,650 °F), CoO is stable.[5][7] These reactions are described by the following equilibrium:
- 2 Co3O4 ⇌ 6 CoO + O2
Applications
[edit]Cobalt(II,III) oxide is used as a blue coloring agent for pottery enamel and glass, as an alternative to cobalt(II) oxide.[8]
Cobalt(II,III) oxide is used as an electrode in some lithium-ion batteries, possibly in the form of cobalt oxide nanoparticles.
Cobalt(III) fluoride can be prepared from cobalt(II,III) oxide by sequential treatment with hydrogen fluoride and then fluorine gas, producing a mixture of cobalt(II) fluoride and cobalt oxyfluoride as intermediates, with overall stoichiometry:[4]
- Co3O4 + 4 HF → CoF2 + 2 CoOF + 2 H2O
- 2 CoF2 + 4 CoOF + 5 F2 → 6 CoF3 + 2 O2
See also
[edit]References
[edit]- ↑ "Cobalt(II,III) oxide 203114". Sigma-Aldrich.
- ↑ Lide, David R., ed. (2006). CRC Handbook of Chemistry and Physics (87th ed.). Boca Raton, Florida: CRC Press. ISBN 0-8493-0487-3.
- ↑ "mp-18748: Co3O4 (cubic, Fd-3m, 227)". materialsproject.org. Retrieved 2019-12-20.
- 1 2 Vilakazi, B. M.; Wagener, J. B.; van der Merwe, E. M. (2020). "A thermogravimetric investigation into the synthesis of CoF3 from Co3O4". Journal of Fluorine Chemistry. 240. doi:10.1016/j.jfluchem.2020.109638.
- 1 2 3 4 Greenwood, Norman N.; Earnshaw, Alan (1997). Chemistry of the Elements (2nd ed.). Butterworth-Heinemann. p. 1118. doi:10.1016/C2009-0-30414-6. ISBN 978-0-08-037941-8.
- ↑ "Guite". mindat.org. Retrieved 2026-03-24.
- ↑ Kwasnik, W. (1963). "4. Fluorine Compounds - Potassium Fluoroborate". In Brauer, Georg (ed.). Handbook of Preparative Inorganic Chemistry. Vol. 2. Translated by Riley, Reed F. (2 ed.). New York, NY: Academic Press. p. 1520.
- ↑ Hamer, Frank; Hamer, Janet (2004). The Potter's Dictionary of Materials and Techniques (5. ed.). Philadelphia, Pa: University of Pennsylvania Press. p. 68. ISBN 0812238109.