Electrochem. transfer behavior of the VVMo11-V5VMo7 heteropolyanions at the water/nitrobenzene interface was investigated by using cyclic voltammetry. The effect of the solution acidity on the transfer behavior and the stable pH range of heteropolyanions were observed Mixed molybdovanadate anions are more stable than 12-molybdophosphoric acid, however, the stability of the former decreases with increasing no. of V atoms. The main transfer species within the "potential window" has the neg. charges of 4 and the transfer process is diffusion controlled. The apparent transfer potential and the free energy, for heteropolyanions can be obtained through the voltammetric data. For different anions, the E1/2-pH relationship can be described as E1/2 = A - 37 pH.

Key words: VANADATE, HETEROPOLYACID, MOLYBDATE, PHOSPHATE, ANION, ELECTROCHEMISTRY, CYCLOVOLTAMGRAPH, INTERFACIAL TRANSFER