Electroanalytical tools to investigate the divalent state of Eu(III) and Nd(III) ions in non-aqueous medium

The divalent state of Ln(III) ions has attracted much interest because of their ability to serve isomorphously in many biological system of divalent Ca(II) ion. Therefore, present paper deals with the study of divalent state of Eu(III) and Nd(III) ions in nonaqueous medium. In present study, cyclic voltammetry and chronopotentiometry were utilized to establish the divalent state of Eu(III) and Nd(III) ions. The cyclic voltammetric technique showed two-step reduction process at cathode for both Ln(III) ions under specified experimental conditions and chronopotentiometric method also showed two different transition times (τ). Looking to the shape of cyclic voltammogram we calculated heterogeneous forward rate constant (K0fh, cm/s) and diffusion coefficient (D, cm2/s) for both ions, which suggested that sweep rate had great effect on the shape of cyclic voltammogram of Eu(III) and Nd(III) ions. The result of chronopotentiometry also suggested that stable divalent states of Eu(III) and Nd(III) ions existed with chronopotentiogram with two distinct transition times. The diffusion coefficients (D, cm2/s) were calculated from Sand equation. The diffusion coefficients of both techniques were compared and the results suggested that the system at electrode surface was changing from being reversible to irreversible.