Carboxylates of rare earth elements

Rare earth carboxylates constitute an enormous group of compounds with various structures and properties. The carboxylate group may be bonded to the metal cations in several ways. The structural aspects of the coordination modes are presented and discussed from the statistical point of view and the most typical groups of carboxylate complexes are reviewed. Data concerning the thermodynamics of formation of the lanthanide, mostly Eu(III), complexes, have been aggregated and briefly analyzed. The electronic spectroscopy of lanthanide carboxylates, mostly focused on analysis of hypersensitive transitions, is discussed for simple carboxylates, acyclic aminopolycarboxylates and dipicolinates, as exemplary systems.