Preparation and conductivity of vanadotungstogermanic heteropoly acid

The vanadotungstogermanic heteropoly acid H5GeW11VO40·22H2O has been prepared for the first time by the stepwise acidification and the stepwise addition of solutions of the component elements. The suitable condition for the synthesis reaction is given. The product was characterized by means of ICP, potentiometric titration, IR, UV, 51V NMR, X-ray powder diffraction and thermal analysis. The result of AC impedance measurement shows that its proton conductivity is 2.43×10−3 S cm−1 at 18°C.