Cadmium hydroxide
Cadmium hydroxide is an inorganic compound with the formula Cd2. It is a white crystalline ionic compound that is a key component of NiCd batteries.Structure, preparation, and reactions
Cadmium hydroxide adopts the same structure as Mg2, consisting of slabs of octahedral metal centers surrounded by octahedral of hydroxide ligands.
It is produced by treating cadmium nitrate with sodium hydroxide:
Attempted preparation from other cadmium salts is more complicated.
Cd2 and cadmium oxide react equivalently. Cadmium hydroxide is more basic than zinc hydroxide. It forms the anionic complex Cd42− when treated with concentrated caustic soda solution. It forms complexes with cyanide, thiocyanate and ammonium ions when added to the solutions of these ions. Cadmium hydroxide loses water on heating, producing cadmium oxide. Decomposition commences at 130 °C and is complete at 300 °C. Reactions with mineral acids produce the corresponding cadmium salts. With hydrochloric acid, sulfuric acid and nitric acid, the products are cadmium chloride, cadmium sulfate and cadmium nitrate, respectively.Uses
It is generated in storage battery anodes, in nickel-cadmium and silver-cadmium storage batteries in its discharge:
