The electrochemical and electrocatalytic properties of iron(III)-substituted Dawson-type tungstophosphate anion are described. The anion exhibits a one-electron couple associated with the Fe(III) center and two two-electron waves attributed to redox processes of the tungsten-oxo framework. All three waves are pH dependent. The anion has a catalytic effect on the reduction of H2O2 and NO2-. The rate constant of the reaction of [P2W17O61(Fe(II) - OH2)]8- with H2O2 was measured using an ultramicroelectrode and was found to be 1.16 x 10(4) M-1 s-1, which is one order of magnitude higher than the reported value for the reaction of H2O2 with iron-substituted Keggin-type heteropoly anion.