Title: Cobaltic-Cobaltous Oxide
CAS Registry Number: 1308-06-1
Additional Names: Cobalto-cobaltic oxide; cobaltosic oxide; tricobalt tetroxide
Molecular Formula: Co3O4
Molecular Weight: 240.80
Percent Composition: Co 73.42%, O 26.58%
Literature 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.
Density: d 6.11
Use: In enamels; in semiconductors; in grinding wheels.