1 PI Hydrogenphosphate ion 1.000 2 2HP Dihydrogenphosphate ion 1.000 3 PO4 Phosphate ion 1.000 4 2PO Phosphonate 0.800 5 78T Oxidanylphosphinate 0.800 6 PHS Phosphonic acid 0.800 7 PO3 Phosphite ion 0.800