Coordination polyhedrons of f-elements in certain extraction systems

A survey of the crystalline data for compounds of rare-earth and trivalent actinide elements is given. The complexes in the extraction of these elements in various extraction systems are considered. The structural characteristics are provided (the coordination number, coordination polyhedron, interatomic distances) for β-diketonate of the rare-earth elements and for complexes of nitrates of the rare-earth elements with dimethyl-sulphoxide. Considered in the paper are complexes produced in the extraction of the rare-earth elements by organophosphorus acids, neutral organophosphorus compounds and amines. In the calculation of extraction equilibria an attempt is made to reduce all the multiplicity of coordination polyhedrons to a set of idealized and originally related configurations