TARTRATE COMPLEXES OF THE RARE-EARTH ELEMENTS: I. THE d-, dl-, AND meso-TARTRATE COMPLEXES OF Tb AND Eu

1963 ◽  
Vol 41 (10) ◽  
pp. 2557-2565 ◽  
Author(s):  
P. G. Manning
Keyword(s):  
Rare Earth ◽  
Ionic Strength ◽  
Sodium Perchlorate ◽  
Ion Association ◽  
Complex Species ◽  
Sodium Tartrate ◽  
Aqueous Sodium ◽  
Coordination Numbers ◽  
Trace Concentrations ◽  
Radiotracer Techniques

Solvent extraction and radiotracer techniques have been applied to the study of metal – tartrate ion association in water at 25 °C. Trace concentrations of the radioisotopes Tb160 and Eu152/154 were equilibrated between aqueous sodium tartrate solutions and organic phases of thenoyltrifluoroacetone in toluene. The ionic strength (0.0597) and the pH (4.53) of the aqueous phase were kept constant by means of sodium perchlorate and sodium acetate.Metal complexing with the d-, dl-, and meso isomers of the ligand was examined. For all isomers two complex species were identified with metal:ligand ratios of 1:1 and 1:2, and stability constants for both stages of ion association have been estimated. No third (1:3) complex was detected.Metal coordination numbers and the formation of tartrate–tartrate hydrogen bridges in the 1:2 complex are discussed.

EUROPIUM OXALATE ION ASSOCIATION IN WATER

1966 ◽  
Vol 44 (24) ◽  
pp. 3057-3062 ◽  
Author(s):  
P. G. Manning
Keyword(s):  
Acetic Acid ◽  
Ionic Strength ◽  
Stability Constant ◽  
Stability Constants ◽  
Aqueous Phase ◽  
Sodium Acetate ◽  
Ion Association ◽  
Sodium Oxalate ◽  
Aqueous Sodium ◽  
Oxalate Ion

The partitioning of radiotracer 152/151Eu between aqueous sodium oxalate (Na2L) solutions and toluene solutions of thenoyltrifluoroacetone (HTTA) has been studied as a function of the oxalate concentration. The pH of the aqueous phase was controlled by means of sodium acetate – acetic acid mixtures and the ionic strength (I) by NaCl or NaClO4.At low ionic strengths (~0.05) and [L] ~10−4 M EuL+ formed, but at I = 0.95 and [L] ~10−3 M EuL2− also formed. Stability constants for the 1:1 and 1:2 (metal:ligand) complexes are reported.The magnitudes of the stepwise stability constant ratios are discussed.

scholarly journals Stability Constant of Rare Earth Metals with Substituted Thiazoles at 298.15K

2016 ◽  
Vol 64 ◽  
pp. 106-109
Author(s):  
A.B. Naik ◽  
M.S. Poharkar
Keyword(s):  
Rare Earth ◽  
Ionic Strength ◽  
Stability Constant ◽  
Rare Earth Metal ◽  
Rare Earth Metals ◽  
Sodium Perchlorate ◽  
Earth Metal ◽  
Water Mixture ◽  
Dissociation Process ◽  
The Stability

The stability constant on complexation of rare earth metal ions Eu (III), Gd (III), Nd (III) and Tb (III) with substituted thiazole in 70% Dioxane (Dx)-water mixture have been determined by a pH and spectrophotometric method at 298.15K and ionic strength 0.1mol.dm-3(sodium perchlorate). At constant temperature, the stability constant of the formed complexes decreases in the order Tb (III), Gd (III), Eu (III), Nd (III). The dissociation process is non-spontaneous, endothermic and entrophically unfavorable while formation of metal complexes has been found to be spontaneous, endothermic and entrophically favorable.

The role of ion-association in the chromatographic separation of isomeric cationic cobalt(III)-amine complexes on cation-exchange resins, particularly SP-Sephadex

1977 ◽  
Vol 30 (12) ◽  
pp. 2625 ◽  
Author(s):  
GH Searle
Keyword(s):  
Cation Exchange ◽  
Ion Pairs ◽  
Sodium Perchlorate ◽  
Ion Association ◽  
Chromatographic Separations ◽  
Sodium Tartrate ◽  
Cation Resin ◽  
Cation Exchange Resins ◽  
Exchange Resins

Chromatographic separations of a set of closely similar or isomeric cobalt(III) complexes, of the kinds [Co(dien)2]3+, [Co(dien)(medien)]3+ and [Co(medien)2]3+ [dien = diethylenetriamine; medien = 4-methyldiethylenetriamine or 2,2'-methyliminodi(ethylamine)] on SP-Sephadex C-25 and Dowex 50W-X2 cation-exchange resins have been examined with different eluents as sodium salts. The separations obtained appear to be due primarily to differences in the association constants for ion-pairs formed betwen the complex cations and the eluent anions, rather than due to differences in affinities of the free cations for the resins. The strengths of the associations depend on: (1) the availability on the complex cations of appropriately disposed N-H bonds for hydrogen-bonding to oxyanions, and probably on the acidities of these hydrogens (acidity sec-NH > NH2), rather than on polarity of charge distribution, and (2) the basicities of anions, in the order PO43- > SeO32- > (+)-tartrate2- > SO42- > (+)-Sb2(C,4H2O6)22- > Cl- ≈ NO3- > ClO4-. The effects of association with PO43-, SeO32- and (+)-tartrate2- may be so great that complex cations of different charges are not necessarily eluted in the order of their increasing charges. Determinations of charges and polarities (cis/trans) of cationic complexes by chromatographic procedures must therefore be carried out under conditions where association is minimized, as with sodium perchlorate as eluent. Under these conditions, separations are determined largely by cation-resin interactions which are less specific and less discriminating than cation-anion interactions. SP-Sephadex is a particularly sensitive medium for separating different cationic complexes, and tri- sodium orthophosphate and sodium (+)-tartrate are the most effective and generally useful eluents.

TARTRATE COMPLEXES OF THE RARE-EARTH ELEMENTS II. THE dl- AND meso-TARTRATE COMPLEXES OF La, Ce, Pm, Tm, AND Y

1963 ◽  
Vol 41 (10) ◽  
pp. 2566-2574 ◽  
Author(s):  
P. G. Manning
Keyword(s):  
Rare Earth ◽  
Ionic Strength ◽  
Stability Constant ◽  
Metal Ion ◽  
Ionic Radius ◽  
Ion Association ◽  
Liquid Distribution ◽  
Distribution Method ◽  
The Stability ◽  
Two Stages

The liquid-liquid distribution method has been used to measure the stability constants of the dl-tartrate complexes of La3+, Ce3+, Pm3+, Tm3+, and Y3+, and the meso-tartrate complexes of Ce3+ and Tm3+. Thenoyltrifluoroacetone was the organic phase extractant, and the aqueous phase, acetate buffered (pH = 4.53), was maintained at a constant ionic strength (0.0597) by means of sodium perchlorate.The order of stabilities for the two stages of ion association are[Formula: see text][Formula: see text]The b1/b2 values, where b is a stepwise stability constant defined as [Formula: see text]are lower (by factors of 4–8) for the dl-tartrates than for the meso-tartrate complexes. The b1/b2 ratios decrease as the ionic radius of the metal ion decreases, and for the dl-tartrates of Tb3+, Y3+, and Tm3+, the b1/b2 values are 5.3, 5.0, and 4.3 respectively. The enhanced stabilities of the 1:2 (ML2−) dl-tartrate chelates have been interpreted in terms of ligand–ligand hydrogen bridging in the 1:2 complex.

Sorption of Cadmium and Lead by Chelating Ion Exchangers Ostsorb OXIN, Ostsorb DETA, and Ostsorb DTTA

1994 ◽  
Vol 59 (6) ◽  
pp. 1311-1318 ◽  
Author(s):  
Ladislav Svoboda ◽  
Petr Vořechovský
Keyword(s):  
Ionic Strength ◽  
Aqueous Solutions ◽  
Sodium Perchlorate ◽  
Exchange Capacity ◽  
Chloride Ions ◽  
Point Of View ◽  
Alkaline Media ◽  
Ion Exchangers ◽  
Acidic Media ◽  
Cadmium And Lead

The properties of cellulose chelating ion exchangers Ostsorb have been studied in the sorption of cadmium and lead from aqueous solutions. The Cd(II) and Pb(II) ions are trapped by the Ostsorb OXIN and Ostsorb DETA ion exchangers most effectively in neutral and alkaline media but at these conditions formation of stable hydrolytic products of both metals competes with the exchange equilibria. From this point of view, Ostsorb DTTA appears to be a more suitable sorbent since it traps the Pb(II) and Cd(II) ions in acidic media already. Chloride ions interfere with the sorption of the two metals by Ostsorb DTTA whereas the ionic strength adjusted by the addition of sodium perchlorate does not affect the exchange capacity of this ion exchanger.

Determination of the complexation properties of a crosslinked poly(acrylic acid) gel with copper(II), nickel(II), and lead(II) in dilute aqueous solution

2001 ◽  
Vol 79 (4) ◽  
pp. 370-376 ◽  
Author(s):  
Catherine Morlay ◽  
Yolande Mouginot ◽  
Monique Cromer ◽  
Olivier Vittori
Keyword(s):  
Aqueous Solution ◽  
Ionic Strength ◽  
Acrylic Acid ◽  
Metal Ion ◽  
Conditional Stability ◽  
Binding Properties ◽  
Complex Species ◽  
Complexing Capacity ◽  
Dilute Aqueous Solution ◽  
Poly Acrylic Acid

The possible removal of copper(II), nickel(II), or lead(II) by an insoluble crosslinked poly(acrylic acid) was investigated in dilute aqueous solution. The binding properties of the polymer were examined at pH = 6.0 or 4.0 with an ionic strength of the medium µ = 0.1 or 1.0 M (NaNO3) using differential pulse polarography as an investigation means. The highest complexing capacity of the polyacid was obtained with lead(II) at pH = 6.0 with µ = 0.1 M, 4.8 mmol Pb(II)/g polymer. The conditional stability constants of the complex species formed were determined using the method proposed by Ruzic assuming that only the 1:1 complex species was formed; for lead(II) at pH = 6.0 and µ = 0.1 M, log K' = 5.3 ± 0.2. It appeared that the binding properties of the polymer increased, depending on the metal ion, in the following order: Ni(II) < Cu(II) < Pb(II). The complexing capacity and log K' values decreased with the pH or with an increase of the ionic strength. These results were in agreement with the conclusions of our previous studies of the hydrosoluble linear analogues. Finally, with the insoluble polymer, the log K' values were comparable to those previously obtained with the linear analogue whereas the complexing capacity values expressed in mmol g-1 were slightly lower.Key words: insoluble crosslinked poly(acrylic acid), copper(II), nickel(II), and lead(II) complexation.

Formation Constants of Copper(II) and Zinc(II) with N-salicylideneanthranilic Acid in 50–50 Water–dioxane

1972 ◽  
Vol 50 (10) ◽  
pp. 1609-1611
Author(s):  
R. K. Mehta ◽  
R K Gupta
Keyword(s):  
Sodium Perchlorate ◽  
Formation Constants ◽  
Protonation Constants ◽  
Fair Agreement ◽  
Complex Species ◽  
Color Changes

Protonation constants of N-salicylideneanthranilic acid and formation constants of its Cu(II) and Zn(II)complexes have been studied potentiometrically in 50% dioxane (vol/vol) solutions (μ = 0.1 sodium perchlorate) at 30 ± 0.2 °C. The color changes observed during titrations have been related to the formation of different complex species in solution. The formation constants are in fair agreement with the Irving and Williams rule.

Freezing and Hydrate Formation in Aqueous Sodium Perchlorate Solutions

2013 ◽  
Vol 639 (6) ◽  
pp. 922-927 ◽  
Author(s):  
Erik Hennings ◽  
Jacob Heinz ◽  
Horst Schmidt ◽  
Wolfgang Voigt
Keyword(s):  
Sodium Perchlorate ◽  
Hydrate Formation ◽  
Aqueous Sodium
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