ABSTRACT
The synergistic solvent extraction of Pr,Gd and Yb with mixtures of 1-phenyl-3-methyl-4-benzoyl-pyrazol-5-one(HP) and a crovm ether benzo-15-crown-5(B15C5 or S) in CCl4,C6H6 and CHC13 has been studied.The composition of the extracted species has been determined as LnP,,nS where LnP3 nS where Lv =Pr, Gd and Yb and n=1 or 2.Mixed complexes LnP3.S have been found when C6H6 and CHC13 were used as diluents and both LnP3.S and LnP3.2S - when CC14 was used.The influence of the diluents on the extraction process has been discussed.