Phosphorus-31 nuclear magnetic resonance study of aluminium(III) ortho-phosphate complexes in aqueous solution

31P NMR spectra have been obtained from a set of aqueous solutions containing Al(ClO4)3-H3PO4-NaH2PO4 mixtures. It was assumed that there is slow exchange on the NMR time scale at the aluminium centre. Peaks corresponding to phosphate containing species have been assigned by correlating observed fractional peak areas with fractional complex concentrations calculated using a model previously proposed on the basis of potentiometric titration data. The results provide strong support for the model.