Cadmium

Abstract

In the natural environment, cadmium is distributed widely but in low concentrations, almost always in conjunction with other elements such as zinc, lead, copper and sulphur. Its principle ore, greenockite, is generally found in conjunction with zinc sulphide (sphalerite). The pure metal - first isolated in 1817 - is bivalent, soft and silverwhite in colour with a relatively low melting point (321 oC). Important cadmium compounds include cadmium oxide, cadmium sulphide, cadmium chloride and cadmium sulphate, the last two of which are soluble in water. The major producers of cadmium are currently in China, Japan and South Korea.