Complex formation constants of nitrate complexes of lanthanides and actinides in the fourth oxidation state

A simple theoretical model is presented for the nitrato complexation of f-elements in the fourth oxidation state and their precipitation with cationic surfactants. The model is based on the assumption of independent ligand binding sites and applies to solutions with high nitrate concentrations. It is successfully used to describe the precipitation data of hexanitrato complexes of Th(IV), Ce(IV) and U(IV) with hexadecylpyridinium nitrate. (orig.)