Cadmium is a soft, malleable, ductile heavy metal with a silvery lustre surface and a low melting point. Similar to tin, typical noises can be heard when bending cadmium of medium purity (with tin, these noises are often referred to as tin cry).
|Melting point||321 °C|
|Boiling point||765° C|
|Melting heat||55 kJ/kg|
|Specific thermal capacity||0.23 kJ/(kg·K)|
|Thermal conductivity||97 kJ/(m·K)|
|Therm. coefficient for linear expansion Coefficient for linear expansion||31·10-6/K|
In chemical compounds the element is mostly divalent. Its chemical structure is similar to that of zinc but it has a greater disposition to form complex compounds. Although resistant in ambient temperature air, under the influence of heat cadmium forms an oxide skin and burns generating a reddish to yellow flame and producing CdO cadmium oxide. CdO is highly toxic.
Cadmium is used as alloy element for bearing materials with good run-in and antifriction properties in the aircraft and automotive industries. Such alloys are used for heavy duty machines running at high speeds with requirements for low wear. In addition to cadmium, they contain additions of copper, silver and nickel.