Related Experiment Video
Updated: Jul 16, 2026

Electrochemical Impedance Spectroscopy as a Tool for Electrochemical Rate Constant Estimation
Published on: October 10, 2018
Electron delocalization in mixed-valence Keggin polyoxometalates. Ab initio calculation of the local effective
Nicolas Suaud1, Alejandro Gaita-Ariño, Juan Modesto Clemente-Juan
1Instituto de Ciencia Molecular, Universidad de Valencia, C/Doctor Moliner 50, 46100 Burjassot, Spain. Nicolas.Suaud@uv.es
Abstract:
We present a quantitative evaluation of the influence of the electron transfer on the magnetic properties of mixed-valence polyoxometalates reduced by two electrons. For that purpose, we extract from valence-spectroscopy ab initio calculations on embedded fragments the value of the transfer integrals between W nearest-neighbor atoms in a mixed-valence alphaPW(12)O(40) polyoxowolframate Keggin anion. In contradiction with what is usually assumed, we show that the electron transfer between edge-sharing and corner-sharing WO(6) octahedra have very close values. Considering fragments of various ranges, we analyze the accuracy of calculations on fragments based on only two WO(5) pyramids which should allow a low cost general study of transfer parameters in polyoxometalates. Finally, these parameters are introduced in an extended Hubbard Hamiltonian that models the whole anion. It permits to prove that electron transfers induce a large energy gap between the singlet ground state and the lowest triplet states providing a clear explanation of the diamagnetic properties of the mixed-valence Keggin ions reduced by two electrons.
Related Concept Videos
Standard Electrode Potentials
π Electron Effects on Chemical Shift: Overview
Ladder Diagrams: Redox Equilibria
Consider the Fe3+/Fe2+ half-reaction, which has a standard-state potential of +0.771 V. At potentials more positive than +0.771 V, Fe3+ predominates, whereas Fe2+...
Electrochemical Systems
The Electrical Double Layer
Processes at Electrodes

