Hydroxocadmiate

Hydroxocadmiate refers to anionic complexes of cadmium. These species typically form in alkaline solutions where cadmium ions (Cd2+) react with hydroxide ions (OH-). The most common hydroxocadmiate species is the tetrahydroxocadmiate(II) ion, [Cd(OH)4]2-. Other possible species include [Cd(OH)]+ in less alkaline conditions or higher hydroxocadmiates depending on the concentration of hydroxide ions.

The formation of hydroxocadmiate complexes influences the solubility of cadmium compounds. Cadmium hydroxide, Cd(OH)2, is generally insoluble in neutral or slightly alkaline water. However, in strongly alkaline solutions, the formation of soluble hydroxocadmiate complexes increases the solubility of cadmium. This phenomenon is important in understanding the behavior of cadmium in environmental systems, such as wastewater treatment or soil chemistry.

Hydroxocadmiate complexes are generally considered to be stable in aqueous solutions. Their exact composition and stability are dependent on factors such as pH, temperature, and the concentration of cadmium and hydroxide ions. The study of these complexes is relevant to inorganic chemistry, environmental science, and analytical chemistry, particularly in the context of cadmium speciation and its potential toxicity.