AN investigation of basic electrochemical behavior of potassium tris(oxalato)ferrate(III).

Abstract

The investigation of the basic electrochem. behavior of K3[Fe(C2O4)3] in various supporting with d.c. polarog. and cyclic voltammetry is reported and the effect of irradn. of light with Hg-lamp on the photoredn. of K3[Fe(C2O4)3] is discussed. Though the electrode reaction (with d.c. polarog. using KCl and NaClO4 as a supporting electrolyte) is irreversible, a linear relation between the diffusion current and the concn. of K3[Fe(C2O4)3] in the range 10-3-10-2 M was obsd. It is also possible to det. the concn. of [Fe(C2O4)3]3- in the range of 10-4-10-2 M, with oscillog. polarog. A proportional relation was not found between diffusion current and the concn. of K3 [Fe(C2O4)3] in the soln. contg. KHC2O4 or H2C2O4 as the supporting electrolyte, but a well-defined reversible wave was obsd. Strong UV irradn. with Hg-lamp accelerates the redn. of [Fe(C2O4)3]3- to [Fe(C2O4)3]4- and a finely dispersed ppt., ferrous hydroxide was obsd. Thus in the polarograms of an irregular wave after the irradn. of light may be due to the adsorption of the ppt. of ferrous and ferric hydroxide on the surface of the electrode. The redox-cycle of Fe(III)-Fe(II)-system by the irradn. of light, the photoredn. of Fe(III) to Fe(II) by Hg-lamp showed that the light irradn. is effective. Max. photoredn. of Fe(III) to Fe(II) in the presence of KCl was ∼66% for 200 min irradn. of UV light. [on SciFinder(R)]