Solvent extraction of calcium and strontium into nitrobenzene by using hydrogen dicarbollylcobaltate in the presence of polypropylene glycol PPG 425

From extraction experiments and γ-activity measurements, the exchange extraction constants corresponding to the general equilibrium M⁺(aq) + Cs⁺(org) ⟺ M⁺(org) + Cs⁺(aq) taking place in the two-phase water–phenyltrifluoromethyl sulfone (abbrev. FS 13) system (M⁺ = Li⁺, H₃O⁺, Na⁺, NH₄⁺ \hbox{NH}_{4}{}^{+} , Ag⁺, Tl⁺, K⁺, Rb⁺; aq = aqueous phase, org = FS 13 phase) were evaluated. Furthermore, the individual extraction constants of the M⁺ cations in the mentioned two-phase system were calculated; they were found to increase in the series of Li⁺ < H₃O⁺ < Na⁺< NH₄ ⁺ \hbox{NH}_{4}{}^{ + } < Ag⁺ < Tl⁺ < K⁺ < Rb⁺ < Cs⁺.