An arsenide (compound) is a compound with arsenic in oxidation state −3, but the term is used loosely. The mineral sperrylite (PtAs2) is called a platinum arsenide, but the formal oxidation state for arsenic is −2. because the solid is usually described as Pt4+,As24-. The description of gallium arsenide (GaAs) is more straightforward since it features isolated arsenic centers.
Arsenides are toxic because of the inherent toxicity of arsenic and all of its compounds.
Metal arsenides react with acids to form highly toxic arsine gas.
See category for a list.