Investigation into solutions of heteropoly acids by the method of correspondence solutions

Aqueous solutions of tungsten- and molybdenum-vanadium heteropoly acids (HPA) of phosphorus and tellurium are investigated by the method of correspondence solutions in a wide concentration range of the central atom (10-5-10-3 mol/l). It is shown that of the whole investigated range tungsten-vanadium complexes of phosphorus and tellurium, containing not more than two vanadium atoms follow the correspondence principle. The tungsten-vanadium HPA solutions are correspondence ones in a wider range of relation Mo:V=11:1-8:4. A proposal is made that the equilibrium character in HPA solutions is mainly defined by the ligand environment rather than the central atom nature. Some recommendations are given concerning the use of HPA following the correspondence principle in the analytical chemistry