Cadmium

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). 

SymbolCd
Atomic number48
Atomic weight112.41
Melting point321 °C
Boiling point765° C
Melting heat55 kJ/kg
Specific thermal capacity0.23 kJ/(kg·K)
Thermal conductivity97 kJ/(m·K)
Therm. coefficient for linear expansion Coefficient for linear expansion31·10-6/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

 


 

Back to list