Title: Cobaltous Arsenate
CAS Registry Number: 7785-24-2
Additional Names: C.I. 77350
Molecular Formula: As2Co3O8
Molecular Weight: 454.64
Percent Composition: As 32.96%, Co 38.89%, O 28.15%
Line Formula: Co3(AsO4)2
Literature References: Octahydrate occurs in nature as erythrite or cobalt bloom. Prepn: Gmelins, Cobalt (8th ed.) 58, (part A), 305 (1932) and supplement, 752 (1961); Charles-Messance et al., Bull. Soc. Chim. Fr. 1962, 574. See Colour Index vol. 4 (3rd ed., 1971) p 4664.
Properties: Octahydrate, pink to blood-red, monoclinic, fine needles. On heating becomes anhydr by 400°. Dec by 1000° to Co6As2O11. d 2.9-3.1. Practically insol in water. Sol in dil mineral acids, in NH4OH.
Density: d 2.9-3.1
Use: Painting on glass and porcelain.