Formal Valence, Charge Distribution, and Chemical Bond in a Compound with a High Oxidation State: KMnO4

• Published in: JETP letters Vol. 117; no. 5; pp. 377 - 383
• Main Authors: Anisimov, V. I., Oganov, A. R., Mazannikova, M. A., Novoselov, D. Y., Korotin, Dm. M.
• Format: Journal Article
• Language: English
• Published: Moscow Pleiades Publishing 01.03.2023; Springer Nature B.V
• Subjects: Atomic; Biological and Medical Physics; Biophysics; Charge distribution; Chemical bonds; Condensed Matter; Configurations; Electron states; Electrons; Hole density; Manganese ions; Molecular; Optical and Plasma Physics; Oxidation; Oxygen atoms; Particle and Nuclear Physics; Physics; Physics and Astronomy; Potassium permanganate; Quantum Information Technology; Solid State Physics; Spintronics; Valence
• ISSN: 0021-3640; 1090-6487
• DOI: 10.1134/S0021364023600143

KMnO 4 has unusual formal manganese oxidation state Mn +7 that seems puzzling: the energy of creating such ion (119 eV) is much greater than the energy of chemical bonds (up to ~10 eV). We have used the Wannier functions formalism to analyze the distribution of Mn- electrons and O- electrons for empty electronic states in the complex and have found that, while formally one has configuration for manganese ion in this compound, in reality only about one-half of the hole density described by these Wannier functions corresponding to this configuration belongs to d -electrons, while the other half is spread over surrounding oxygen atoms. This corresponds much more to Mn +7 state than to Mn +2 , because the calculated total number of d ‑electrons is equal to 5.25. Our analysis has also sown nearly perfect covalent type of chemical bond within the complex with negligible contribution of the ionic part.