When finely divided it decomposes water giving hydrogen phosphide; it also reduces sulphurous and sulphuric' acids, and when boiled with water gives phosphine and hypophosphorous acid; when slowly oxidized under water it yields, hypophosphoric acid.
The metal can be reduced by magnesium, zinc, cadmium, iron, tin, copper and substances like hypophosphorous acid from acid solutions or from alkaline ones by formaldehyde.
Rose; liquid phosphuretted hydrogen was first obtained by Thenard in 1838; and hypophosphorous acid was discovered by Dulong in 1816.
Oxyacids.-Phosphorus forms several oxyacids: hypophosphorous acid, H 3 P0 2, and hypophosphoric acid, H 4 P 2 0 6 or H2P03, of which the anhydrides are unknown; phosphorous acid, H 3 P0 3, derived from P 4 0 5; monoperphosphoric acid, H 3 P0 5; perphosphoric acid, H4P208; and meta-, pyro-, and ortho-phosphoric acids, derived from P4010, for which see Phosphates.
The replacement is more readily brought about by the use of sodium stannite (P. Friedlander, Ber., 1889, 22, p. 587), or by the use of a concentrated solution of hypophosphorous acid (J.
Wurtz's first published paper was on hypophosphorous acid (1842), and the continuation of his work on the acids of phosphorus (1845) resulted in the discovery of sulphophosphoric acid and phosphorus oxychloride, as well as of copper hydride.