ABSTRACT
I. ION PAIRS AND FREE IONS A. Introduction Carbanions, free radicals, and carbocations are reaction intermediates. An intermediate is defined as a transient chemical species, with a lifetime appreciably longer than a molecular vibration (corresponding to a local potential energy minimum or depth greater than RT), that is formed (directly or indirectly) from the reactants and reacts further to give (either directly or indirectly) the products of a chemical reaction [1]. Unlike most other reaction intermediates, a wide variety of carbanions can be prepared, isolated and characterized. This chapter will review the nature of carbanions in solution, especially their interaction with counterions, and their stereochemistry.
