Sodium hypophosphite is an inorganic compound with the chemical formula NaH2PO2. It is a colorless crystal or white powder with pearl luster. It is salty and deliquescent. Intensive heating will liberate phosphine and immediately catch fire in the air. Mixing with strong oxidants will cause an explosion. Easily soluble in glycerin and hot ethanol, soluble in water and cold ethanol, slightly soluble in absolute ethanol, insoluble in ether. The aqueous solution is neutral. It is obtained by neutralizing hypophosphorous acid with sodium carbonate. Used as a reducing agent in medicines, laboratory reagents and nickel plating.

Colorless crystals or pearly crystals or granular powder. It is soluble in water, alcohol and glycerin, but insoluble in ether. Easily deliquescent. It is a strong reducing agent that can reduce metal salts such as gold, silver, platinum, mercury, and nickel into a metallic state. Phosphine precipitated under strong heat can ignite spontaneously, and explode in contact with chlorate and oxidant. Decompose when heated to 200°C.