Complexing of californium(III) and other trivalent actinides by inorganic ligands

Abstract

Stability constants of the complexes of Cf(III) with Cl −, NO 3 −, SCN − and SO 4 2−: Cm(III) with Cl −, NO 3 − and SO 4 2− and Am(III) with SO 4 2− have been determined at 30°C in ammonium ion media of unit ionic strength by a solvent extraction method. Except in the Am(III)SO 4 2− system where only the first complex exists all the other systems indicate the presence of the first two complexes. The higher stability of Cf(SCN) 2 + in comparison with that of Am(SCN) 2 + and Cm(SCN) 2 + has been attributed to increased availability of 5ƒ orbitals for bond formation. The relative importance of inner and outer-sphere character in the complexes of trivalent actinides with inorganic ligands used has been discussed. Extraction of trivalent actinides and lanthanides by the quaternary amine Aliquat-336 from chloride, thiocyanate, nitrate and sulphate media was investigated and indicate increased stability after Cm(III)in anionic chloride, thiocyanate and nitrate complexes of trivalent actinides.