Ferrous hypophosphite, Fe(H₂PO₂)₂

Ferrous hypophosphite, Fe(H₂PO₂)₂, results on dissolving iron in hypophosphorous acid, air being carefully excluded. The metal dissolves with evolution of hydrogen gas, and the salt passes into solution. It is also obtained by double decomposition of solutions of ferrous sulphate and the barium salt. Ferrous hypophosphite crystallises in green octahedra, which readily oxidise on exposure to air.