Ferric hypophosphite, Fe(H₂PO₂)₃

Ferric hypophosphite, Fe(H₂PO₂)₃, is obtained as an insoluble white powder on dissolving freshly precipitated ferric hydroxide in dilute hypophosphorous acid in the cold, and allowing to evaporate. It decomposes on warming, yielding a mixture of ferrous and ferric hypo-phosphites; on warming with acids an evolution of hydrogen phosphide takes place.