9 - Inorganic reactions and their mechanisms

Summary

Introductory remarks

In this chapter we try to classify the more important types of reactions encountered in inorganic chemistry, and describe some of their mechanisms. The emphasis is placed upon the principles which determine the stability or instability, existence and nonexistence of inorganic substances from the viewpoint of the ease or otherwise of preparing a compound, and the tendency a compound — once prepared — may have to react spontaneously to give other products. Both thermodynamic and kinetic considerations are obviously involved here. The division of material between this chapter and the next has not been easy, and there is inevitably a good deal of overlap. Coupling reactions, which might have deserved a section in this chapter, are discussed in Sections 10.5 and 10.6.

Organic chemists are usually concerned with homogeneous — i.e. single-phase — reactions of molecular substances in inert solvents. The classification of such reactions and their mechanisms is relatively simple. Inorganic chemists, however, have to deal with reactions involving gases, solids and liquids/solutions and often have to consider heterogeneous equilibria. In solution, the solvent may play an active part, both in the thermodynamic and kinetic aspects of the reaction. Nor is the inorganic chemist dealing almost exclusively with molecular substances.