Stabilisation of metal ions in unusual oxidation states and electron dynamics in oxide glasses

The results of studies on the stabilisation of metal ions in unusual oxidation states in oxide glasses are surveyed. Attention is concentrated on the relation between the stabilisation of these ions and redistribution of the electron density, and on the disproportionation reactions accompanying it. The effect of reversible low-temperature disproportionation on niobium, titanium, vanadium, molybdenum, tungsten, and other ions is considered. The formation of metal clusters in oxide glasses is shown also to be associated with disproportionation. The bibliography includes 108 references.