ORGANIC SOLUTIONS CONTAINING COMPLEXES OF LANTHANIDE NITRATES WITH TRI-NORMAL-BUTYLPHOSPHATE AND DI-(2-ETHYLHEXYL) PHOSPHORIC-ACID

Dilute solutions of TBP and DEHP in cyclohexane and benzene (T = 310.1 5 K) are studied by vapor pressure osmometry. Dimerization constants a nd Kirkwood-Buff integrals are calculated. Complexes of Ce(III), Nd, G d, Er, and Yb(III) nitrates with TBP and DEHP are synthesized. The ext ractant:metal ratio in the complexes with TBP is less than 3; in those with DEHP, in the range 3.4-3.6. Complexes ZnA3 (A is the anion of DE HP) are isolated. Their solubility in DEHP decreases with increasing a tomic number. Osmometric investigations of isomolal series of DEHP-TBP mixtures (1), TBP-TBP-solvates (2), and TBP-solvates-DEHP (3) reveal positive deviations from additivity for the number of particles only i n solutions (3).