Cadmium chloride is an inorganic salt with the formula CdCl2. It is commonly described as the binary halide of cadmium and chloride and may be defined in the context of a chemical compound. In the solid state it typically appears as a white crystalline material; it is hygroscopic and readily forms hydrated species when exposed to moist air. In aqueous solution it dissociates to provide ions and is a convenient source of Cd2+ for laboratory and industrial syntheses. The metal is in the +2 oxidation state in this compound (oxidation state +2).

Physical and chemical properties

Cadmium chloride is soluble in polar solvents such as water and some alcohols. The anhydrous and hydrated forms have different crystal structures; cadmium centers are commonly six-coordinate, giving octahedral environments with chloride ligands in extended layers. The material can participate in coordination chemistry and form complex salts with a variety of ligands. It reacts with sulfide, carbonate and many other reagents to yield insoluble cadmium compounds or organometallic derivatives.

Preparation and reactions

Common laboratory methods prepare cadmium chloride by treating cadmium metal, cadmium oxide or carbonate with hydrochloric acid under controlled conditions, followed by purification and drying to obtain anhydrous or hydrated forms. It serves as a precursor to other cadmium salts and to cadmium-containing materials used in research and some manufacturing processes.

Uses

  • Reagent in organic and inorganic synthesis and in analytical chemistry.
  • Precursor for cadmium-containing pigments, catalysts and some semiconductor thin films.
  • Specialized electroplating and surface-treatment baths where cadmium deposition is required under regulated conditions.

Safety and regulation

Cadmium chloride and other cadmium compounds are toxic and potentially carcinogenic with risks from inhalation, ingestion and dermal exposure. They are persistent and can bioaccumulate in the environment; therefore many countries regulate their manufacture, use and disposal. Work with cadmium chloride requires engineering controls, appropriate personal protective equipment, training and waste-management procedures to limit exposure and environmental release.