In chemistry, intervalence charge transfer, often abbreviated IVCT or even IT, is an electron transfer (thermal or photoinduced) between two metal sites differing only in oxidation state. Quite often such electron transfer reverses the oxidation states of the sites. The term is frequently extended to the case of metal-to-metal charge transfer between non-equivalent metal centres. The process can be described as follows: LnM+-bridge-M'Ln + hν → LnM-bridge-M'+Ln where L is a ligand.