Nomenclature
CAS number: 1307-96-6
CoO; mol wt 74.93.
Co 78.65%, O 21.35%.
Description and references
Prepn: Amiel et al., Compt. Rend. 259, 3512 (1964);
Wilke, Z. Anorg. Allg. Chem. 330, 164 (1964). Toxicity study: Smyth et al., Am. Ind. Hyg. Assoc. J. 30, 470 (1969). Review: de Bie, Doyen, Cobalt 15, 3-13; 16, 3-15 (1962).
Properties
Powder, or cubic or hexagonal crystals. Color
varies from olive green to red, depending on the particle size, but
the commercial material is usually dark grey and contains about 76%
Co. mp ≈1935°. d 5.7 to 6.7, depending
on method of prepn. Readily absorbs O2 even at room temp.
Practically insol in water. Sol in acids or alkalies. Easily reduced
to Co by C or CO. Reacts at high temperatures with silica, alumina,
zinc oxide to form pigments. LD50 orally in rats: 1.70 g/kg (Smyth).Note
The commercial oxides are usually not
definite chemical compds but mixtures of the cobalt oxides.Use
In pigments for ceramics; glass coloring and decolorization;
oxidation catalyst for drying oils, fast-drying paints and varnishes;
prepn of cobalt-metal catalysts, Co powder for binder in sintered
tungsten carbide; in semiconductors.