Chapter 4 - Mechanisms and Reactions in the Solid State

Abstract

This chapter explores the reaction of solids that includes the mechanisms involved when solids form by reaction from constituent compounds. The chapter also describes some methods of measurement and how one determines extent and rate of the solid state reaction actually taking place. It shows how the presence and/or formation of point defects affect reactivity in solid state reactions. Inorganic solids do not react by either changing the bonding within a molecular structure or by reacting one-on one in a mobile phase such as a liquid, as the organic compounds. Solids can only react at the interface of another solid, or in the case of a liquid solid reaction, reacts with the liquid molecule at the solid interface. Mechanisms related to solid state reaction include phase changes, formation of phase boundaries, rate process changes in solids, nucleation, diffusion processes, and diffusion-controlled solid state reactions. Solid state reaction is dependent upon the rate of diffusion. The chapter also examines some of the mathematics used to define rate processes in solid state reactions.