Metal ions in unusual and unstable oxidation states in aqueous solutions: preparation and properties

The properties of short-lived metal atoms and ions in unusual oxidation states in aqueous solutions, characterised by the presence of one electron in the outer s or p orbitals (the d¹⁰s¹ and d¹⁰s²p¹ configurations respectively), are discussed. The results of studies on such ions by pulse radiolysis with rapid optical detection and by the matrix isolation method in frozen aqueous solutions are presented. The nature of the dependences of fundamental characteristics of metal atoms and ions (optical transition energies, the electronic structures of various complexes, the oxidation–reduction potentials, etc.) on their positions in the Periodic System are analysed. The bibliography includes 93 references.