Topic summary
Phosphonic acid
Extracted from the Wikipedia article Phosphorous acid.
Phosphorous acid (or phosphonic acid) is the compound described by the formulaH3PO3. It is diprotic (readily ionizes two protons), not triprotic as might be suggested by its formula. Phosphorous acid is an intermediate in the preparation of other phosphorus compounds. Organic derivatives of phosphorous acid, compounds with the formula RPO3H2, are called phosphonic acids.