Cadmium (Cd) is a soft, silvery-white metal that exists in two main oxidation states, +2 and +1. It does not typically behave as a transition metal due to partially filled d and f electron shells, and is therefore usually considered a Group 12 element. When cadmium burns in air, it produces cadmium oxide (CdO), which is deep red in its crystalline form and acquires a different color when heated. Cadmium chloride (CdCl2), cadmium sulfate (CdSO4), or cadmium nitrate (Cd(NO3)2) are formed by dissolving cadmium in hydrochloric acid, sulfuric acid, or nitric acid, respectively. Cadmium forms Cd2+ ions similar to Hg2+ ions in the mercury chloride of CdCl2 and alumina chloride. Cadmium compounds with numerous structures are known, including complexes with amino acids and vitamins. Cadmium naturally occurs in eight different isotopes. Three of them decay into non-radioactive forms and two are radioactive, but they have not been measured in laboratory conditions to a significant extent, and the other three -112Cd, 113Cd, and 115Cd - are very rare. Cadmium is produced through beta emission in the s-process that occurs over thousands of years in low to intermediate mass stars such as silver atoms. An atom of gold loses a neutron during this process and then undergoes beta decay. Source: Wikipedia
