ABSTRACT
This chapter considers a chemical reaction mechanism to be "a specification, by means of a sequence of elementary chemical steps, of the detailed process by which a chemical change occurs". These elementary chemical steps may themselves be described by providing "a picture of the participating species at one or more crucial instants during the course of the reaction". These characterizations of mechanism are drawn from relatively contemporary texts in theoretical organic chemistry, which limits how robustly applicable they are. The chapter also considers the notion of mechanism applicable in this subfield because it was the field in which reaction mechanisms first emerged in modern chemistry. In 1903, Lapworth published an account of the mechanism of the addition reaction supported by kinetic studies. His speculations about reaction mechanisms clearly show how rate data can be used to decompose a chemical reaction into elementary reactions which themselves are consistent with the guiding principle of reaction kinetics.
