Extraction of strontium and barium into nitrobenzene by using synergistic mixture of hydrogen dicarbollylcobaltate and polyethylene glycol PEG 1000

Abstract

Extraction of microamounts of strontium and barium by a nitrobenzene solution of hydrogen dicarbollylcobaltate (H⁺B⁻) in the presence of polyethylene glycol PEG 1000 (L) has been investigated. The equilibrium data have been explained assuming that the complexes ${\text{H}}_{ 2} {\text{L}}^{2 + }$, ${\text{ML}}^{ 2+ }$ and ${\text{MHL}}^{ 3+ }$ $\left( {{\text{M}}^{ 2+ } = {\text{Sr}}^{ 2+ } ,\,\,{\text{Ba}}^{ 2+ } } \right)$ 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 constant of the ${\text{BaL}}^{ 2+ }$cationic complex species is somewhat higher than that of the complex ${\text{SrL}}^{ 2+ }$.