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Cobalt(III) oxide

Cobalt(III) oxide[1]
Names
IUPAC name
cobalt(III) oxide, dicobalt trioxide
Other names
cobaltic oxide, cobalt sesquioxide
Identifiers
3D model (JSmol)
ChemSpider
ECHA InfoCard 100.013.779 Edit this at Wikidata
EC Number
  • 215-156-7
RTECS number
  • GG2900000
  • InChI=1S/2Co.3O
    Key: UPWOEMHINGJHOB-UHFFFAOYSA-N
  • O=[Co]O[Co]=O
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
-577 kJ/mol
Hazards
Occupational safety and health (OHS/OSH):
Main hazards
 toxic
GHS labelling:
GHS07: Exclamation markGHS08: Health hazard
Warning
H302, H317, H351, H410
P280
NFPA 704 (fire diamond)
NFPA 704 four-colored diamondHealth 3: Short exposure could cause serious temporary or residual injury. E.g. chlorine gasFlammability 0: Will not burn. E.g. waterInstability 0: Normally stable, even under fire exposure conditions, and is not reactive with water. E.g. liquid nitrogenSpecial hazard OX: Oxidizer. E.g. potassium perchlorate
3
0
0
OX
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(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

References

  1. ^ Sigma-Aldrich product page
  2. ^ Lide, David R., ed. (2006). CRC Handbook of Chemistry and Physics (87th ed.). Boca Raton, FL: CRC Press. ISBN 0-8493-0487-3.
  3. ^ "1308-04-9 CAS MSDS (COBALT(III) OXIDE BLACK) Melting Point Boiling Point Density CAS Chemical Properties".
  4. ^ Greenwood, Norman N.; Earnshaw, Alan (1997). Chemistry of the Elements (2nd ed.). Butterworth-Heinemann. ISBN 978-0-08-037941-8.
  5. ^ Handbook of Preparative Inorganic Chemistry, 2nd Ed. Edited by G. Brauer, Academic Press, 1963, NY. p. 1675.
  6. ^ Hüttner, Erwin (1901-05-02). "Beiträge zur Kenntnis der Oxyde des Kobalts". Zeitschrift für anorganische Chemie (in German). 27 (1). Wiley: 81–124. doi:10.1002/zaac.19010270113. ISSN 0863-1778.
  7. ^ 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. 5 (45). American Chemical Society (ACS): 29009–29016. doi:10.1021/acsomega.0c03397. ISSN 2470-1343. PMC 7675568. PMID 33225132.
  8. ^ 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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