Cobaltous Bromide

Title: Cobaltous Bromide
CAS Registry Number: 7789-43-7
Additional Names: Cobalt dibromide
Molecular Formula: Br2Co
Molecular Weight: 218.74
Percent Composition: Br 73.06%, Co 26.94%
Line Formula: CoBr2
Literature References: Prepn of hexahydrate from CoCO3 and HBr: Clark, Buchner, J. Am. Chem. Soc. 44, 230 (1922). Prepn of anhydr: eidem, loc. cit.; Watt et al., ibid. 77, 2752 (1955); Wydeven, Gregory, J. Phys. Chem. 68, 3249 (1964).
Properties: Bright green solid or lustrous green cryst leaflets. mp 678° (under HBr and N2); d425 4.909. Hygroscopic, forms hexahydrate in air. Readily sol in water, methanol, ethanol, acetone, methyl acetate.
Melting point: mp 678° (under HBr and N2)
Density: d425 4.909
Derivative Type: Hexahydrate
Properties: Red to reddish-purple, deliquesc, prismatic crystals. mp 47-48°. d425 2.46. Loses 4H2O at 100° giving the purple dihydrate, and all H2O by 130°. Sol in water giving red or blue soln depending on concn and temp, in methanol giving red soln, in ethanol, acetone, ether, methyl acetate giving blue solns. Keep well closed.
Melting point: mp 47-48°
Density: d425 2.46
Use: Chiefly in hygrometers; also in catalysts for organic reactions.
Cobaltous Carbonate Cobaltous Chloride Cobaltous Chromate(III) Cobaltous Cyanide Cobaltous Fluoride