Surface sites of microcrystals: Coordination and reactivity

Studies on powders are of great interest in all fields of materials science. For fundamental research, it is relevant to determine the structure of solids at the "boundary" with the external environment where relaxation, reconstruction, adsorption and related phenomena occur. In the case of technological research, application for catalysis, pigments, etc., detailed information are required on morphology of the particles, surface structure, optical properties, adsorptive capacities and so on. The relations between structure and activity of surface sites of typical microcrystalline samples are here focused giving particular emphasis to the role of the coordination of the active centres.