Compounds of Cobalt

General Properties of Compounds of Cobalt - Cobalt, in its salts, behaves both as a trivalent and a divalent element, although the trivalent salts are unstable except in the case of double salts. The colour of cobalt salts varies greatly according to the degree of hydration, but it is usually pink or blue. Cobalt salts absorb nitric oxide, and with ammonia readily yield complex ammino derivatives.

Pure cobalt salts free from nickel may be obtained from the impure derivatives.