Centre Énergie Matériaux Télécommunications, Institut National de la Recherche Scientifique, 1650 Boulevard Lionel-Boulet, Varennes, QC J3X 1S2, Canada.
School of Materials and Chemical Technology, Tokyo Institute of Technology, Ookayama 2-12-1, Meguro-ku, Tokyo 152-8552, Japan.
Molecules. 2021 Sep 13;26(18):5541. doi: 10.3390/molecules26185541.
Description of redox reactions is critically important for understanding and rational design of materials for electrochemical technologies, including metal-ion batteries, catalytic surfaces, or redox-flow cells. Most of these technologies utilize redox-active transition metal compounds due to their rich chemistry and their beneficial physical and chemical properties for these types of applications. A century since its introduction, the concept of formal oxidation states (FOS) is still widely used for rationalization of the mechanisms of redox reactions, but there exists a well-documented discrepancy between FOS and the electron density-derived charge states of transition metal ions in their bulk and molecular compounds. We summarize our findings and those of others which suggest that density-driven descriptors are, in certain cases, better suited to characterize the mechanism of redox reactions, especially when anion redox is involved, which is the blind spot of the FOS ansatz.
氧化还原反应的描述对于理解和合理设计电化学技术的材料至关重要，包括金属离子电池、催化表面或氧化还原流电池。由于其丰富的化学性质以及对这些类型应用的有益物理和化学性质，这些技术大多利用氧化还原活性过渡金属化合物。自引入一个世纪以来，形式氧化态（FOS）的概念仍然广泛用于合理化氧化还原反应的机制，但 FOS 与过渡金属离子在其体相和分子化合物中的电子密度衍生电荷态之间存在有据可查的差异。我们总结了我们的发现和其他人的发现，这些发现表明，在某些情况下，密度驱动的描述符更适合于表征氧化还原反应的机制，特别是当涉及阴离子氧化还原时，这是 FOS 方法的盲点。
