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  • Author or Editor: E. Makrlík x
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Abstract  

Extraction of microamounts of barium by a nitrobenzene solution of ammonium dicarbollylcobaltate (NH4 +B-) in the presence of 15-crown-5(15C5,L) has been investigated. The equilibrium data have been explained assuming that the complexes NH4L+, NH4L2 + and BaL2 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.

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Abstract  

From extraction experiments with 85Sr as a tracer, the extraction constant corresponding to the equilibrium Sr2+(aq) + 2A- (aq) + 2L (nb) Û SrL2 ,2+ (nb) 2A- (nb) in the two-phase water-nitrobenzene system (A- = picrate, L = benzo-15-crown-5; aq = aqueous phase, nb = nitrobenzene phase) was evaluated as log K ex

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Abstract  

Solvent extraction of microamounts of europium and cerium 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 species H2L2+ and ML3+ (M3+ = Eu3+, Ce3+) are extracted into the organic phase. The values of extraction and stability constants of the complexes in nitrobenzene saturated with water have been determined. It was found that the stability constants of the cationic complex species EuL3+ and CeL3+ in water-saturated nitrobenzene are practically the same.

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Abstract  

From extraction experiments and γ-activity measurements, the exchange extraction constants corresponding to the general equilibrium M2+ (aq) + SrL2+ (nb)
\documentclass{aastex} \usepackage{amsbsy} \usepackage{amsfonts} \usepackage{amssymb} \usepackage{bm} \usepackage{mathrsfs} \usepackage{pifont} \usepackage{stmaryrd} \usepackage{textcomp} \usepackage{upgreek} \usepackage{portland,xspace} \usepackage{amsmath,amsxtra} \pagestyle{empty} \DeclareMathSizes{10}{9}{7}{6} \begin{document} $$\Leftrightarrow$$ \end{document}
ML2+ (nb) + Sr2+ (aq) taking place in the two-phase water–nitrobenzene system (M2+ = Ca2+, Pb2+, Cu2+, Zn2+, Cd2+,
\documentclass{aastex} \usepackage{amsbsy} \usepackage{amsfonts} \usepackage{amssymb} \usepackage{bm} \usepackage{mathrsfs} \usepackage{pifont} \usepackage{stmaryrd} \usepackage{textcomp} \usepackage{upgreek} \usepackage{portland,xspace} \usepackage{amsmath,amsxtra} \pagestyle{empty} \DeclareMathSizes{10}{9}{7}{6} \begin{document} $${\text{UO}}_{2}^{2 + }$$ \end{document}
, Mn2+, Co2+, Ni2+; L = hexaethyl p-tert-butylcalix[6]arene hexaacetate; aq = aqueous phase, nb = nitrobenzene phase) were evaluated. Moreover, the stability constants of the ML2+ complexes in nitrobenzene saturated with water were calculated; they were found to increase in the following order: Cd2+ < Ca2+ < Mn2+ < Cu2+, Zn2+ < 
\documentclass{aastex} \usepackage{amsbsy} \usepackage{amsfonts} \usepackage{amssymb} \usepackage{bm} \usepackage{mathrsfs} \usepackage{pifont} \usepackage{stmaryrd} \usepackage{textcomp} \usepackage{upgreek} \usepackage{portland,xspace} \usepackage{amsmath,amsxtra} \pagestyle{empty} \DeclareMathSizes{10}{9}{7}{6} \begin{document} $${\text{UO}}_{2}^{2 + }$$ \end{document}
, Co2+ < Ni2+ < Sr2+ < Pb2+.
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Abstract  

From extraction experiments and γ-activity measurements, the extraction constant corresponding to the equilibrium Na+(aq)+HL+(nb)⇆NaL+(nb)+H+(aq) taking place in the two-phase water-nitrobenzene system (L=18-crown-6; aq=aqueous phase, nb=nitrobenzene phase) was evaluated as logK ex (Na+,HL+)=0.1. Further, the stability constant of the 18-crown-6-sodium complex in nitrobenzene saturated with water was calculated: logβ nh(NaL+)=8.0.

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Abstract  

From extraction experiments and γ-activity measurements, the extraction constant of the Ba2+ (aq)+SrL2/2+(nb)⇆⇆BaL2/2+ (nb)+Sr2+(aq) equilibrium taking place in a two-phase water-nitrobenzene system (L=15-crown-5; aq-aqueous phase, nb=nitrobenzene phase) was evaluated as logK ex(Ba2+,SrL2/2+)=1.8. Further, the stability constant of the BaL2/2+ complex in water saturated nitrobenzene was calculated to be log βnh(BaL2 2+)=16.5.

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Abstract  

Extraction of sodium by the nitrobenzene solution of H+ bis-1,2-dicarbollylcobaltate (H+B) in the presence of 15-crown-5 (15C5, L) has been investigated. The equilibrium data have been explained assuming that the complexes HL+, HL2 + NaL+ and NaL2 +, NaL+ and NaL2 + are extracted into the organic phase. The values of extraction and stability constants of the species in nitrobenzene saturated with water have been determined.

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Abstract  

From extraction experiments and γ-activity measurements, the exchange extraction constants corresponding to the general equilibrium M+(aq)+NaL+(nb)⇄ML+(nb)+Na+(aq) taking place in the two-phase water-nitrobenzene system (M+=Li+, K+, Rb+, Cs+; L=dibenzo-24-crown-8; aq=aqueous phase, nb=nitrobenzene phase) were evaluated. Further, the stability constants of the ML+ complexes in nitrobenzene saturated with water were calculated; they were found to increase in the Cs+Rb+L+Na+ order.

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Abstract  

From extraction experiments and γ-activity measurements, the extraction constant corresponding to the equilibrium 2Na+(aq)+SrL2 2+(nb)⇆ 2NaL+(nb)+Sr2+(aq) taking place in the two-phase water-nitrobenzene system (L=15-crown-5; aq=aqueous phase, nb=nitrobenzene phase) was evaluated as logK ex(2Na+,SrL2 2+)=−1.6. Further, the stability constant of the 15-crown-5-sodium complex in nitrobenzene saturated with water was calculated: log βnb(NaL+)=7.3.

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Abstract  

The extraction of microamounts of cesium by a nitrobenzene solution of sodium bis-1,2-dicarbollylcobaltate (Na+B) in the presence of 15-crown-5 (15C5, L) has been investigated. The equilibrium data have been explained assuming the complexes NaL+, NaL2 +, CsL+ and CsL2 + to be extracted into the organic phase. The values of extraction and stability constants of the species in nitrobenzene saturated with water have been determined.

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