Cobalt(II,III) oxide

From Wikipedia, the free encyclopedia
Jump to: navigation, search
Cobalt(II,III) oxide[1]
Cobalt(II,III) oxide
Ball-and-stick model of the unit cell of Co3O4
IUPAC name
cobalt(II) dicobalt(III) oxide
Other names
cobalt oxide, cobalt(II,III) oxide, cobaltosic oxide, tricobalt tetroxide
3D model (JSmol)
ECHA InfoCard 100.013.780
RTECS number GG2500000


Molar mass 240.80 g/mol
Appearance black solid
Density 6.11 g/cm3
Melting point 895 °C (1,643 °F; 1,168 K)
Boiling point 900 °C (1,650 °F; 1,170 K) (decomposes)
Solubility soluble in acids and alkalis
+7380·10−6 cm3/mol
R-phrases (outdated) R40 R41 R42 R43
S-phrases (outdated) S36/37
NFPA 704
Flammability code 0: Will not burn. E.g., water Health code 2: Intense or continued but not chronic exposure could cause temporary incapacitation or possible residual injury. E.g., chloroform Reactivity code 0: Normally stable, even under fire exposure conditions, and is not reactive with water. E.g., liquid nitrogen Special hazards (white): no codeNFPA 704 four-colored diamond
Except where otherwise noted, data are given for materials in their standard state (at 25 °C [77 °F], 100 kPa).
N verify (what is YesYN ?)
Infobox references

Cobalt(II,III) oxide is an inorganic compound with the formula Co3O4. It is one of two well characterized cobalt oxides. It is a black antiferromagnetic solid. As a mixed valence compound, its formula is sometimes written as CoIICoIII2O4 and sometimes as CoO•Co2O3.[2]


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.[2]

tetrahedral coordination geometry of Co(II) distorted octahedral coordination geometry of Co(III) distorted tetrahedral coordination geometry of O


Cobalt(II) oxide, CoO, converts to Co3O4 upon heating at around 600-700 °C in air.[3] Above 900 °C, CoO is stable.[3][4] These reaction are described by the following equilibrium:

2 Co3O4 ⇌ 6 CoO + O2


Cobalt compounds are potentially poisonous in large amounts.[5]

See also[edit]


  1. ^ Sigma-Aldrich product page
  2. ^ a b Greenwood, Norman N.; Earnshaw, Alan (1997). Chemistry of the Elements (2nd ed.). Butterworth-Heinemann. p. 1118. ISBN 0-08-037941-9. 
  3. ^ a b Greenwood, Norman N.; Earnshaw, Alan (1997). Chemistry of the Elements (2nd ed.). Butterworth-Heinemann. p. 1118. ISBN 0-08-037941-9. 
  4. ^ Handbook of Preparative Inorganic Chemistry, 2nd Ed. Edited by G. Brauer, Academic Press, 1963, NY. p. 1520.
  5. ^ MSDS[permanent dead link]