Extraction of barium by a nitrobenzene solution of bis-1,2-dicarbollylcobaltate in the presence of 15-crown-5

Extraction of barium by a nitrobenzene solution of bis-1,2-dicarbollylcobaltate in the presence of 15-crown-5 (15C5, L) has been investigated. The equilibrium data and the typical maxima concerning the dependencies of the Ba distribution ratios on the analytical concentration of 15C5 in the system under study can be explained assuming that the particles HL+, HL2+ and BaL22+ are extracted into the nitrobenzene phase. The values of the corresponding extraction and stability constants of the extracted species in nitrobenzene saturated with water have been determined.