Chelation and the stability constants of metal complexes

Abstract

The link between this chapter and the preceding ones is the fact that those ionic species which can bind a hydrogen cation have an affinity, also, for the cations of metals. Usually this affinity is greatest when an organic molecule is so designed that it can form at least two bonds to the metal, thus creating a ring. This ringformation is called chelation, from the Greek word for the lobster’s claw, and the complexing species is known as a ligand. A complexant (chelating agent) may have two or more ionic species, but often only one of these is the ligand.