Cadmium oxide

Overview
Cadmium oxide is an inorganic compound with the formula CdO. CdO is one of the main precursors to other cadmium compounds It crystallizes in a cubic lattice like sodium chloride, with octahedral cation and anion centers.

Production and structure
Since cadmium compounds are often found in association with zinc ores, cadmium oxide is a common by-product of zinc refining. . It is produced by burning elemental cadmium in air. Pyrolysis of other cadmium compounds, such as the nitrate or the carbonate, also affords this oxide. When pure, it is red but CdO is unusual in being available in many differing colours due to its tendency to form defect structures resulting from anion vacancies.

Reactivity
CdO is a basic oxide and is thus attacked by aqueous acids to give solutions of [Cd(H2O)6]2+. Upon treatment with strong alkaline solutions, [Cd(OH)4]2- forms.

Health Risks
Cadmium compounds are considered carcinogenic.