Inorganic Arsenic Compounds other than Arsine Health and Safety Guide - Health and Safety Guide 70

Arsenic compounds are often unstable, and in many cases are not well defined materials. For example, the arsenites of the alkali metals are slowly converted in solution to arsenates, by atmospheric oxygen. Arsenic trisulfide reacts vigorously with oxidizing agents, and hydrogen sulfide is generated on contact with strong acids. Arsenic trichloride is highly reactive with water, strong oxidants, ammonia, and some alkalis; the reaction results in the generation of hydrogen chloride and chlorine gas.