Cadmium is a highly toxic metal and is known to cause cancer. This rare element is found in the mineral greenockite, but is obtained mainly as a by-product of zinc mining. Cadmium was discovered in 1817 from a mineral called hemimorphite. Today, this metal is mainly used together with nickel in rechargeable batteries. Cadmium oxide, CdO2, was formerly used to prepare red paints, but due to its toxicity it is no longer used. Cadmium is also used to create lasers for powerful microscopes.

Summary of properties (Cd)

Atomic weight112.414(4)
Discoverer (year)Stromeyer, Prof. Friedrich (1817)
Natural formmetallic solid (hexagonal)
Electron configuration[Kr] 4d10 5s2
Melting point (ºC)321
Boiling point (ºC)765
Abundance in earth's crust (ppm)0.15
Isotope (abundance)106Cd (1.25), 108Cd (0.89), 110Cd (12.49), 111Cd (12.80), 112Cd (24.13), 113Cd (12.22), 114Cd (28.73), 116Cd (7.49)
Density g/cm38.65
Van der Waals radius (pm)218
Covalent radius (pm)140
Electronegativity (Pauling)1.69
Vaporization enthalpy (kJ/mol)99.87
Enthalpy of fusion (kJ/mol)6.19
Specific heat capacity (J/g·K) at 25ºC and 1 atm0.23
Thermal conductivity (W/cm·K) at 25ºC and 1 atm0.970
Oxidation state+2
Electron affinity (eV)unstable ion
1st Ionization potential (eV)8.9938

Back to the Periodic Table of the Elements.