Metal-organic materials: strategies towards functional porous materials

Abstract

Lecturesspecialists in order to investigate the structures of aperiodic crystals including incommensurately modulated crystals, composites and quasicrystals.Composite and modulated structures occur in almost every type of solids including organic and inorganic compounds, minerals, metals and alloys and even in proteins.The study of their structures has greatly contributed to identify and understand the interactions occurring in crystals.Numerous phenomena, which were partially understood, could be reinterpreted on the basis of the incommensurability of structures.The superspace formalism appears to be particularly suited for the description of modular structures, i.e. structures sharing common building units.This has been applied to a series of technologically important class of compounds including perovskites, ferrites and sheelites.In some favourable case, the full series of compounds can be described with a single parameter, characterising the chemical composition of each member.The presentation is intended to illustrate the evolution of the superspace concept since it was introduced some four decades ago.