Extraction of thallium with cesium dicarbollylcobaltate in the presence of18-crown-6

From extraction experiments with Cs-134 as a tracer, the extraction constan t corresponding to the equilibrium Tl+(aq)+CsL+(nb) reversible arrow TIL+ ( nb) + Cs+(aq) taking place in a two-phase water-nitrobenzene system (L = 18 -crown-6; aq = aqueous phase, nb = nitrobenzene phase) was determined as lo g K-ex(Tl+, CsL+) = 1.5 +/-0.1. Further, the stability constant of the comp lex TIL+ in nitrobenzene saturated with water was evaluated for a temperatu re of 25 degreesC: log beta (nb)(TIL+) = 9.2 +/-0. 1. Finally, the individu al extraction constant of the TIL+ species in the water-nitrobenzene system corresponding to the equilibrium TIL+(aq) reversible arrow TIL+(nb) was ca lculated as log K-TIL(i). = 2.5 +/-0. 1.