CADMIUM, Cd, = 112.

This is a somewhat rare metal, found associated with zinc in nearly all its ores, and obtained from these by distillation.

Characters And Tests

Tin-white and lustrous, fibrous in fracture, ductile and malleable, of sp. gr. 8.6 to 8.9. In air, at ordinary temperatures, it tarnishes gradually; heated strongly it takes fire, and burns to a brown oxide, CdO; at 176° F. it becomes very brittle, and fuses at 442° F. Treated with dilute mineral acids, it sets free hydrogen, and forms a colorless solution; this, when further diluted, gives with sulphuretted hydrogen a bright yellow precipitate of cadmium sulphide (CdS), insoluble in ammonium sulphide. Caustic and carbonated alkalies give with cadmium salts gelatinous white precipitates, which, except in the case of ammonia, are insoluble in excess. Zinc precipitates metallic cadmium.