Cobalt(II,III) oxide is an inorganic compound with the formula . Along with cobalt(II) oxide, it is one of two well characterized and stable cobalt oxides. It is a black antiferromagnetic solid. As a mixed valence compound, its formula is sometimes written as and sometimes as . It occurs naturally as the rare mineral guite which is named in honor of Prof. Xiangping Gu (1964-).
Structure adopts the normal spinel structure, with ions in tetrahedral interstices and ions in the octahedral interstices of the cubic close-packed lattice of oxide anions.
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 upon heating at around in air. Above , 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.
Cobalt(III) fluoride can be prepared from cobalt(II,III) oxide by sequential treatment with hydrogen fluoride and then fluorine gas, producing a mixture of cobalt(II) fluoride and cobalt oxyfluoride as intermediates, with overall stoichiometry:
See also Cobalt(II) oxide Cobalt(III) oxide
References