Cobalt(II,III) oxide

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 Co^IICo^III₂O₄ and sometimes as CoO•Co₂O₃.^[4]

Cobalt(II,III) oxide^[1]

Cobalt(II,III) oxide
Ball-and-stick model of the unit cell of Co3O4
Names
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
3D model (JSmol)	Interactive image
ChemSpider	9826389 Y
ECHA InfoCard	100.013.780
EC Number	215-157-2
PubChem CID	11651651
RTECS number	GG2500000
UNII	USK772NS56 Y
CompTox Dashboard (EPA)	DTXSID80892420
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
SMILES [Co]=O.O=[Co]O[Co]=O
Properties
Chemical formula	Co3O4 CoO.Co2O3
Molar mass	240.80 g/mol
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)
Solubility in water	Insoluble
Solubility	soluble (with degradation) in acids and alkalis
Magnetic susceptibility (χ)	+7380·10−6 cm3/mol
Structure
Crystal structure	cubic
Space group	Fd3m, No. 227[3]
Hazards
GHS labelling:
Pictograms
Signal word	Danger
Hazard statements	H317, H334, H350, H411
Precautionary statements	P261, P273, P284, P304+P340, P342+P311
NFPA 704 (fire diamond)	2 0 0
Except where otherwise noted, data are given for materials in their standard state (at 25 °C [77 °F], 100 kPa). N verify (what is YN ?) Infobox references

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.^[4]

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 upon heating at around 600–700 °C in air.^[4] Above 900 °C, CoO is stable.^[4][5] These reactions are described by the following equilibrium:

2 Co₃O₄ ⇌ 6 CoO + O₂

Applications

Cobalt(II,III) oxide is used as a blue coloring agent for pottery enamel and glass, as an alternative to cobalt(II) oxide.^[6]

Cobalt(II,III) oxide is used as an electrode in some lithium-ion batteries, possibly in the form of cobalt oxide nanoparticles.

Safety

Cobalt compounds are potentially poisonous in large amounts.^[7]

See also

• Cobalt(II) oxide
• Cobalt(III) oxide