SOLID-STATE REACTIONS OF INORGANIC COMPOUNDS. Elena V. Boldyreva^* . Institute of Solid State Chemistry Siberian Department of the Russian Academy of Sciences. Kutateladze, 18, Novosibirsk, 128, 630128 Russia

There are so many different types of "solid-state reactions of inorganic compounds", that it may seem impossible to cover such a topic within a 20 minute lecture. What can formation of a complex oxide in the powder mixture of simple metal oxides have in common with the photo-isomerization in coordination compounds, with an intercallation - reaction, or with the decomposition of metal azides, crystal hydrates, or KMnO₄? The present contribution is aimed to give an answer to this question. Looking for something common between absolutely different types of solid-state reactions of inorganic compounds, we shall concentrate our attention on the role of crystal structure in a solid-state transformation.

We shall start with the static aspects of the effect of crystal structure on the solid-state transformations. The crystal structure will be considered as a "frame" determining the mutual juxtaposition of the reacting chemical species, as well as the size, the shape, and the mutual orientation of the channels serving for the transport of ions, atoms, or molecules. Examples of epitaxial and topotactic solid-state reactions will be given, the methods of "soft chemistry" and the "precursor technique" will be discussed.

We shall proceed then with considering the dynamic aspects of the effect of the crystal structure on the solid-state transformations. We shall demonstrate that the strain induced in the crystal structure by the reaction can be the main factor, determining the kinetics and the spatial pattern of the reaction, as well as the structure, the morphology, and thus, the properties of solid products.

^*In 1995-1996 - a Humboldt Fellow at the Institute of Physical Chemistry Marburg University.