Hypophosphite

The hypophosphite ion is H2PO2&minus;, hypophosphorous acid minus one hydrogen ion.

Hypophosphites are the compounds containing this ion, with phosphorous in oxidation state +1, or similar covalent ones.

Two hydrogens are attached directly to the phosphorus atom.

The IUPAC (mostly organic) name for the same ion is phosphinate. This is virtually not ever used for hypophosphite ion itself, with both hydrogens remaining, but for substituted ions. For example, "dimethylphosphinate" ion would be (CH3)2PO2&minus;.

The hypophosphite ion is thermodynamically unstable, and disproportionates on heating:


 * 2 H2PO2&minus; → PH3 + HPO42&minus;