Solvent extraction of strontium and barium into nitrobenzene by using hydrogen dicarbollylcobaltate in the presence of dicyclohexano-24-crown-8

Extraction of microamounts of strontium and barium by a nitrobenzene solution of hydrogen dicarbollylcobaltate (H(+)B(-)) in the presence of dicyclohexano24- crown-8 (DCH24C8, L) has been investigated. The equilibrium data have been explained assuming that the complexes HL(+), HL(2)(+), ML(2+) and ML(2)(2+) (M(2+) = Sr(2+), Ba(2+)) are extracted into the organic phase. The values of extraction and stability constants of the species in nitrobenzene saturated with water have been determined. It was found that in water saturated nitrobenzene, the stability constants of the complexes BaL(2+) and BaL(2)(2+), where L = DCH24C8, are somewhat higher than those of the corresponding species SrL(2+) and SrL(2)(2+) with the same ligand L.