The phosphine selenides, tris (dimethylamino) phosphine selenide, esters of selenophosphoric acid, and esters of selenophosphonic acid react with dihalogens and sulfuryl chloride to form halogenoselenophosphonium salts (P–SeX)+ X−. The latter undergo deselenization via ligand exchange to form phosphonium salts (P–X)+ X− and elemental selenium. The stability of these salts depends on the substituents at the ...