Synergistic Extraction of Some Univalent Cations into Nitrobenzene by Using Sodium Dicarbollylcobaltate and Dibenzo-21-crown-7.

: 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+, H+, NH+4, Ag+, K+, Rb+, Tl+, Cs+; 1 = dibenzo-21-crown-7; aq = aqueous phase, nb = nitrobenzene phase) were evaluated. Furthermore, the stability constants of the 1•M+ complexes in water - saturated nitrobenzene were calculated; they were found to increase in the series of H+ < Ag+ < Li+ < Cs+ < K+, Rb+ < NH+4 < Tl+.