The Lewis Acid-Base Definitions: A Status Report

This is not so much a proper review, in the sense of being a detailed survey of current experimental work, as it is a retrospective essay on the current status of the Lewis acid-base definitions as a systematizing tool in chemistry. Indeed, as the main concern is with the nature of the Lewis definitions themselves, their range of application, their limitations, the clarification of interpretive or semantic problems, etc., this essay might be most accurately characterized as a review of monographs and reviews which, in turn, deal with the raw experimental data. The Lewis definitions are now over a half-century old. To what extent has the work on organometallic compounds, for example, or on new nonaqueous or molten salt solvent systems, or the addition of new bonding concepts to the traditional two-center, two-electron bond and octet rule available to Lewis tended to repudiate or confirm the value of the Lewis definitions? It is hoped that this review will convince the reader that the devel-