In oxy acids, phosphorus is tetrahedrally surrounded by other atoms. Atleast one P=O bond and one P−OH bondis present. Oxyacids ( in which phosphorous has lower oxidation state) contains either P−P bond or P−H bond but not both. The oxyacids with +3 oxidation state of phosphorous disproportionate. Some examples of oxyacids of phosphorous include hypophosphorous acid H3PO2, orthophosphorous acid H3PO3, pyrophosphorous acid H4P2O5, hypophosphoric acid H4P2O6 and orthophosphoric acid H3PO4.