Summary The action of alkali on tetrakis (hydroxymethy1) phosphonium chloride has been shown to take place in two stages, giving first tris (hydroxymethy1) phosphonium oxide and finally bis (hydroxymethy1) phosphinic acid and liberating one molecule of hydrogen at each stage. With a neutral carbonate the action stops at the oxide stage. Tetrakis (chloromethy1) phosphonium chloride was prepared from the corresponding hydroxy derivative by ...