2429. Cobaltic-Cobaltous Oxide

Nomenclature

CAS number: 1308-06-1
Cobalto-cobaltic oxide; cobaltosic oxide; tricobalt tetroxide.
Co3O4; mol wt 240.80.
Co 73.42%, O 26.58%.

Description and references

Prepn: Gmelins, Cobalt (8th ed.) 58 (Part A), 231-235 (1932) and supplement, 202, 491-496 (1961). Review: de Bie, Doyen, Cobalt 15, 3-13; 16, 3-15 (1962).

Properties

Black or grey octahedral crystals of cubic system. d 6.11. Commercial material is black and contains about 71% Co. Above 900° loses O2 to form CoO; absorbs O2 at lower temps but cryst structure is unchanged. Absorbs water but no definite hydrate has been identified. Readily reduced to Co metal by C, CO, or H2. Practically insol in water. Sol in acids, alkalies.

Use

In enamels; in semiconductors; in grinding wheels.