The electroactive species Fe2+ can be transported easily through the thin films of KVFe(CN)6 (I) to the underlaying glassy C electrode surface to be oxidized directly at less pos. potential, and it can also be oxidized at the film at more pos. potential by means of redox sites in the film. These 2 processes yield clearly distinguished sequential 1st and 2nd waves in steady-state current-potential curves resulting from use of a rotating-disk electrode. The plateau current of the 1st wave is limited by the diffusion rate of Fe2+, both in the solution and in the film. The permeability parameter, kDm/d, of the I film to Fe2+ is of the order of 10-3-10-2 cm/s, which decreases linearly with an increase in film thickness and remains constant when the bulk concentration of Fe2+ in the solution varies.

Key words: IRON ION, DYNAMICS, THIN FILMS, VANADIUM COMPOUNDS, CHARGE TRANSFER, FERROCYANIDE