Issues in the energetics of metastable oxides kand oxyhydroxides

摘要

In both low temperature materials synthesis (sol gel processing, chimie douce) and low temperature geochemistry (weathering, geothermal and hydrothermal reactions, diagenesis) metastable and/or poorly crystalline materials are encountered. Despite the lack of equilibrium, energetic considerations play a major role in the formation of zeolites and related metastable framework, on nanophase alpha and gamma alumina, and on manganese oxides and hydroxides are summarized. These studies illustrate the effects of framework topology, cation content, hydration and surface energy on the formation, persistence, and eventual transformation to more stable phase assemblages of these environmentally important materials.