Electrochemical Behavior of Ytterbium Trichloride in Oxygenated Organic Solvents

While all lanthanides have a stable trivalent oxidation state, three lanthanides are known to form divalent states: europium, ytterbium, and samarium. While the divalent states of europium and samarium have been extensively studied under various experimental conditions, little research has been done on divalent ytterbium. Herein, the electrochemical behavior and kinetics of the Yb(III)/Yb(II) redox couple are investigated in three oxygenated solvents (dimethyl sulfoxide, N,N‐dimethylformamide, and ethylene glycol). Passivation effects and the effect of low water concentrations on the redox behavior are investigated by cyclic and linear‐sweep voltammetry. The presence of water is found to have a diminishing effect on the observed passivation. A kinetic study of Yb(III) is conducted using cyclic voltammetry and linear sweep voltammetry with a rotating disc electrode, an approach not previously applied to the Yb(III) reduction in organic systems. Koutecký–Levich analysis is applied to accurately determine electrochemical rate constants. The electrochemical behavior of Yb(III) varies significantly as the solvent distinctly influences the stabilization of the different oxidation states. The Yb(III)/Yb(II) redox couple is found to be quasi‐reversible in each solvent system, and the calculated parameters align with previously reported values for Eu and Sm systems as well as with those obtained from simulations.