Cobalt(II,III) oxide

Cobalt(II,III) oxide[1]
IUPAC name cobalt(II) dicobalt(III) oxide
Other names cobalt oxide, cobalt(II,III) oxide, cobaltosic oxide, tricobalt tetroxide
Identifiers
CAS number	1308-06-1 Y
ChemSpider	9826389 Y
RTECS number	GG2500000
Jmol-3D images	Image 1
SMILES [Co]=O.O=[Co]O[Co]=O
InChI InChI=1S/3Co.4O Y Key: LBFUKZWYPLNNJC-UHFFFAOYSA-N Y InChI=1/3Co.4O/rCo2O3.CoO/c3-1-5-2-4;1-2 Key: LBFUKZWYPLNNJC-PMPQCLQHAA
Properties
Molecular formula	Co3O4 CoO.Co2O3
Molar mass	240.80 g mol−1
Appearance	black solid
Density	6.11 g/cm3
Melting point	895 °C
Boiling point	900 °C (decomposes)
Solubility in water	Insoluble
Solubility	soluble in acids and alkalis
Hazards
R-phrases	R40 R41 R42 R43
S-phrases	S36/37
NFPA 704	0 2 0
Y oxide (verify) (what is: Y/N?) Except where noted otherwise, data are given for materials in their standard state (at 25 °C, 100 kPa)
Infobox references

Cobalt(II,III) oxide is 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 Co^IICo^III₂O₄ and sometimes as CoO.Co₂O₃.^[2]

Structure

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

Synthesis

Cobalt(II) oxide, CoO, converts to Co₃O₄ if heated to around 1000 °C in air. Above 900 °C, CoO is stable.^[3] These reaction are described by the following equilibrium:

Co₃O₄ $\overrightarrow{\leftarrow}$ 3 CoO + 1/2 O₂

Research

This inorganic compound is currently utilized in the process of artificial photosynthesis. Artificial photosynthesis is being used to create an alternative liquid fuel.

Safety

Cobalt compounds are potentially poisonous in large amounts.^[4]

References

1. ^ Sigma-Aldrich product page
2. ^ ^{a b} Greenwood, Norman N.; Earnshaw, Alan (1997). Chemistry of the Elements (2nd ed.). Oxford: Butterworth-Heinemann. p. 1118. ISBN 0080379419. 
3. ^ Handbook of Preparative Inorganic Chemistry, 2nd Ed. Edited by G. Brauer, Academic Press, 1963, NY. p. 1520.
4. ^ MSDS