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. It occurs naturally as the rare mineral guite which is named in honor of Prof. Xiangping Gu (1964-).

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.

Synthesis

Cobalt(II) oxide, CoO, converts to Co₃O₄ upon heating at around 600–700 Ã‚°C in air. Above 900 Ã‚°C, CoO is stable. These reactions are described by the following equilibrium:

Applications

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

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

See also

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

References