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Cobalt (Metallic element at wt symbol)

a metallic element, at. wt. 59, symbol Co. The metal was first obtained in an impure state by Brandt, in 1733. It occurs as speiss cobalt, or tinwhite cobalt CoAs2, and cobalt-glance, CoAsS. Cobalt occurs in meteoric iron.

Metallic cobalt is a hard, magnetic, duetile, reddish-gray metal, with a high COBALT melting point. Its sp. gr. is 8.9. It is not easily oxidized by the air, when pure.

It is dissolved by dilute HCl or H₂SO₄ HCl or H2SO4 with evolution of hydrogen Cobalt forms two oxides: Cobaltous oxide CoO and Cobaltic oxide Co2O3. The alloys of cobalt are unimportant. Zaffre is an impure oxide of cobalt prepared by roasting cobalt ores with twice their weight of sand. Smalt is prepared by fusing their weight partially roasted cobalt ores with a mixture of powdered quartz and potassium carbonate; while hot it is poured into water and then ground to a fine powder; it is used as a pigment; this color was known to the ancients. The cobaltous salts are the most stable in which cobalt acts as a dyad element. Cobalt compounds give a blue color to a borax bead. There is no native cobalt known, but many ores of the metal. Arsenate or Arseniate of Cobalt Erythrite ; Arsenical Cobalt Smaltite; Black Cobalt Asbolite; Bright-white Cobalt= Oobalt-glance; Carbonate of Cobalt = Remingtonite; Earthy Cobalt Asbolite; Gray Cobalt= Smaltite; Red Cobalt = Erythrite; Sulphate of Cobalt Bieberite ; Sulphuret of Cobalt Syepoorite, Linnæite; White Cobalt=Smaltite; Cobalt and Lead Selenite Tilkerodite. Ammonia cobaltous salts are formed by the union of cobaltous salts with ammonia in excess, the air being excluded, being excluded , as, CoCl2.6NH3, rosecolored crystals.

They are formed when an ammoniacal solution of cobalt is exposed to the air .