An approach is suggested in order to investigate the mechanism of interfacial electron-transfer processes with reagents of nonspherical form and complicated charge distribution. Chelate chromium(III) ethylenediaminetetraacetate (EDTA) complexes are regarded as a good model system. A series of SCF quantum chemical calculations at the ZINDO/1 level were performed for the systems Cr(EDTA)(H2O)(n)(-)(n = 0, 1, 2, 3, and 4). A quinquedentate complex Cr(EDTA)H2O- was found to be energetically more favorable compared to Cr(EDTA)(-). The interaction of Cr(EDTA)(-) with a cadmium electrode (modeled as a 19-atomic planar cluster) was investigated as well. The analysis of both the potential energy surfaces and the partial charge transfer allows the explanation of the absence of "specific" interaction between Cr(EDTA)(-) complexes and mercury-like metals observed experimentally. A way to estimate the inner-sphere contribution (E-in) to reorganization energy is proposed. The inner-sphere asymmetry (nonequality of (E-in) values for reduction and oxidation) was found, which plays a significant role in the theoretical analysis of the activation energy. To obtain estimates of the solvent reorganization energy, the shape of reagents was approximated by ellipsoids. The detailed atomic charge distribution in oxidized and reduced complexes was employed to provide a "microscopic" description of electrical double layer effects. Additional ab initio SCF calculations with several basis sets of different quality were performed for the analysis of the charge distributions. The activation energies for several orientations of Cr(EDTA)(-) and Cr(EDTA)H2O- relative to the metal surface were calculated for two values of the electrode charge densities. It is concluded that a sufficient interpretation of relevant experimental data is not possible without calculations of the reaction pre-exponent.