Solid-State Reactions of Inorganic Materials

Elena Boldyreva

Institute of Solid State Chemistry and Mechanochemistry SB RAS,

Kutateladze, 18, Novosibirsk, 128, RUSSIA, and

Novosibirsk State University, Pirogova, 2, Novosibirsk, 90, RUSSIA

The topic mentioned in the title is too broad to be covered in a 45-minutes lecture. I shall therefore limit my presentation to a very general introduction into the problem referring to a few examples. The main emphasis will be made neither on the materials, nor on the inorganic nature of the compounds, but on the solid state reactivity. The main reason for this is that the general problems related to the synthesis, manufacturing, shelf-life and exploitation stability, utilization, etc. are common for the materials based on the compounds of very different chemical nature, even for inorganic and organic solids. What is important is that the compounds are solid.

The fact, that a compound involved in a chemical reaction is solid, has a number of consequences. Firstly, not individual molecules are participating in a reaction, but large assemblies of atoms, ions, molecular ions, and this results in many cooperative effects and in the properties, which cannot, in principle, characterize an individual molecule. Secondly, the species in a solid have a limited mobility as compared with liquids and gasses, the solids are poorly penetrable and resist attempts to change their shape and volume. This results in several problems related to bringing reagents into a contact and to removing the reaction products, as well as to the structural reconstruction, in particular - to phase transitions - accompanying solid-state chemical reactions. Strain and stress play an important role both in solid-state reactivity and in the exploitation stability of solid materials. Many properties can be determined by the presence of the defects of various types.

In the lecture the abovementioned aspects of the solid-state reactivity will be illustrated by several selected examples.