Synthesis and real structure of inorganic materials

Abstract

The generation of new or known inorganic compounds with specific chemical and physical properties is discussed. Inorganic solid state chemistry comprising the interrelated topics 'Reactivity of Solids' and 'Heterogeneous Solid State Reactions' gets most relevant, As a consequence processes of the type Z Solids I + Z Gases I # Z Solids I1 + Z Gases I1 need to be studied with respect to an optimization of the experimental conditions under which the desired products are obtained. Thus, not only the selection of appropriate parent solids, but also the knowledge of the role of the volatile agents are considered as indispensable prerequisites. Moreover, it is necessary to pay due attention to topochemical aspects, and to emphasize detailed investigations on structural relationships between the solids involved, i.e. 'Topotary'. Influences of the actual reactive or inert gas atmosphere as well as the actual pressure on the course of reaction and thus on the product formation are used for the generation of materials with specific properties. Finally, features of the 'Real Structure' of the so-formed mono- or multiphasic materials, comprising morphology, size of particles, domain structures, etc., are described. Quantitative thermal analysis combined with independent complementary techniques such as X-ray diffraction, light and electron microscopy, simultaneous mass spectrometry or gas chromatography, etc., prove to represent well-suited tools for such studies. The determination of kinetic data is conducive in order to get further insights into the fundamental problem of establishing correlations between macroscopic and microscopic reaction mechanism. As illustrative examples the controlled generation of microcrystalline materials from suitable precursor phases such as mixed metal carbonates, oxides or coordination compounds are described. The products - catalytically relevant dispersed metals or alloys on oxidic supports, mono- or biphasic transition metal sulfides, etc. - represent members of a framework which constitutes the basis for the generation of 'tailor-made inorganic materials'.