IntervallenceLadungstransferBand

Intervallence charge transfer, often abbreviated as IVCT, is a phenomenon observed in mixed-valence compounds. These are chemical species that contain at least two metal ions or atoms of the same element in different oxidation states. IVCT refers to the electronic transition that occurs when an electron moves between these ions or atoms with different valencies. This movement is not a simple transfer of charge but rather a delocalized process.

The energy required for this transition is typically in the visible or near-infrared region of the electromagnetic spectrum, making mixed-valence compounds often intensely colored. The intensity and energy of the IVCT band are highly dependent on the degree of delocalization of the electron between the metal centers, the nature of the bridging ligands connecting them, and the specific oxidation states involved.

Studies of IVCT are important for understanding electron transfer processes in various chemical and biological systems. It provides insights into the mechanisms of redox reactions, the design of materials for electronic and optical applications, and the functioning of metalloenzymes. The Robin and Day classification system is a widely used framework for categorizing mixed-valence compounds based on the extent of electron delocalization, which directly influences the IVCT properties.