Chemistry:Cobalt(III) oxide
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| Names | |
|---|---|
| IUPAC name
cobalt(III) oxide, dicobalt trioxide
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| Other names
cobaltic oxide, cobalt sesquioxide
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| Identifiers | |
3D model (JSmol)
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| EC Number |
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PubChem CID
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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 | |
| Main hazards | toxic |
| GHS pictograms |  
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| GHS Signal word | 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). | |
 verify (what is   ?)
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| Infobox references | |
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
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
- Cobalt Oxide Nanoparticles
References
- ↑ Sigma-Aldrich product page
- ↑ Lide, David R., ed (2006). CRC Handbook of Chemistry and Physics (87th ed.). Boca Raton, FL: CRC Press. ISBN 0-8493-0487-3.
- ↑ "1308-04-9 CAS MSDS (COBALT(III) OXIDE BLACK) Melting Point Boiling Point Density CAS Chemical Properties". http://www.chemicalbook.com/ChemicalProductProperty_US_CB4291419.aspx.
- ↑ Greenwood, Norman N.; Earnshaw, Alan (1997). Chemistry of the Elements (2nd ed.). Butterworth-Heinemann. ISBN 978-0-08-037941-8.
- ↑ Handbook of Preparative Inorganic Chemistry, 2nd Ed. Edited by G. Brauer, Academic Press, 1963, NY. p. 1675.
- ↑ Hüttner, Erwin (1901-05-02). "Beiträge zur Kenntnis der Oxyde des Kobalts" (in de). Zeitschrift für anorganische Chemie (Wiley) 27 (1): 81–124. doi:10.1002/zaac.19010270113. ISSN 0863-1778. https://zenodo.org/record/2455069.
- ↑ Shanbhag, Pavitra N.; Biswas, Raju K.; Pati, Swapan K.; Sundaresan, Athinarayanan; Rao, Chinthamani Nagesa Ramachandra (2020-11-02). "Elusive Co2O3: A Combined Experimental and Theoretical Study". ACS Omega (American Chemical Society (ACS)) 5 (45): 29009–29016. doi:10.1021/acsomega.0c03397. ISSN 2470-1343. PMID 33225132.
- ↑ Guoqing, Wu (2003). 无机化学 (Inorganic Chemistry) (4th ed.). People's Republic of China: 高等教育出版社 (Higher Education Press). p. 781. ISBN 9787040115833.
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