Extraction of some univalent cations into nitrobenzene by using a synergistic mixture of sodium dicarbollylcobaltate and barium ionophore I

From extraction experiments and γ-activity measurements, the exchange extraction constants corresponding to the general equilibrium M⁺ (aq) + 1·Na⁺ (nb) ⇔ 1·M⁺ (nb) + Na⁺ (aq) taking place in the two-phase water–nitrobenzene system (M⁺ = Li⁺, H₃O⁺, NH₄ ⁺ {\rm NH}_{4}^{ + } , Ag⁺, K⁺, Rb⁺, Tl⁺, Cs⁺; 1 = barium ionophore I; aq = aqueous phase, nb = nitrobenzene phase) were determined. Furthermore, the stability constants of the 1·M⁺ complexes in water-saturated nitrobenzene were calculated; they were found to increase in the series of Cs⁺ < Rb⁺ < NH₄ ⁺ {\rm NH}_{4}^{ + } , K⁺ < H₃O⁺ < Na⁺ < Ag⁺, Tl⁺ < Li⁺.