2442. Cobaltous Hydroxide

Nomenclature

CAS number: 21041-93-0
CoH2O2; mol wt 92.95.
Co 63.40%, H 2.17%, O 34.43%.
Co(OH)2.

Description and references

Prepd from a solution of a cobaltous salt and an alkali hydroxide: Glemser in Handbook of Preparative Inorganic Chemistry vol. 2, G. Brauer, Ed. (Academic Press, New York, 2nd ed., 1965) p 1521; Weiser, Milligan, J. Phys. Chem. 36, 722 (1932). Review: de Bie, Doyen, Cobalt 15, 3-13; 16, 3-15 (1962).

Properties

Blue-green or rose-red powder or microscopic rhombohedral crystals; red form is the more stable of the two. d415 3.597. Easily oxidized by air or weak oxidizing agents to Co(OH)3. Amphoteric. Loses water on heating, forming CoO at 168° in vacuo. Very slightly sol in water; readily sol in acids; practically insol in dil alkalies; sol in ammonia.

Use

Manuf of Co compds; drier for paints; in enhancing drying properties of lithographic printing inks; in storage battery electrode impregnating solns.