Dehydroxylation of hydroxides

Valence deficient oxygen species (O, 022, 033") produced by a) ionizing radiation and associated with lattice defects b) N20 or 6 adsorption, possibly followed by incorporation of O into the lattice c) thermal dehydroxylation of hydroxides in part via ... 

Peroxide formation may intervene [50] during dehydroxylation of hydroxides of the following metals Ba, Al, Cd, Zn and Pb. This conclusion was reached from the observation that during the reactions of these salts with alkali halides elemental halogen was liberated. These reactions need further investigation. 

The dissociations of transition-metal oxides have often been studied as later processes following the dehydration/dehydroxylation of hydroxides. The existence of polymorphic varieties of the oxide systems has inhibited rapid development of this field. Descriptions of behaviour tend to be predominantly qualitative, devoted to the recognition of the phases involved, the sequences of changes which occur and the crystallographic relationships (if any) between reactants and products in each transformation. 

Oxides can be prepared by dehydration or dehydroxylation of hydroxides, whose preparation is usually the critical step. Medium temperatures are used and the process may lead to formation of metastable species for instance, Ti02-B can be prepared by calcination of Ti407(0H)2 H20 at 500 °C in air. 

---