Ionic self-diffusion coefficients of (III) in solutions in water - dioxan mixtures at

Abstract

The measurement of ionic self-diffusion coefficients of the lanthanide ions (III) in asymmetrical electrolytes (3:1) solutions of in hydro-organic water - dioxan mixtures (at a low dielectric constant) gives evidence of the progressive association of ion pairs. The study of different physical - chemical properties in all the domains of composition shows the existence of three regions with distinct behaviours. The application of association theory to such an asymmetrical electrolyte (3:1) with a polyvalent cation enables us to delimit the validity of the Bjerrum and Fuoss theories.

Investigations of the ionic self-diffusion coefficients of the trivalent lanthanide152Eu(III) in diluted Eu(ClO4)3solutions in 1,4-dioxane + water mixtures at 298.15 K

“…Then, the variation of log K A is quasi-linear for an a-parameter adjusted to the effective radius r (Figure 8). Equation (29) can be transformed in this case to the following equation, when our experimental conditions are considered: log K A ¼ À2:60 þ 3 logðað-ÞÞ þ 730:12 " Á að-Þ ð30Þ…”

“…Furthermore, the use of the dielectric constant in polyvalent ion solutions can hardly be considered as shown by Anderson and Saddington [27]. After previous investigation of self-diffusion of 153 Gd(III) in the system of 1,4-dioxanewater þ 2 Â 10 À4 mol L À1 Gd(NO 3 ) 3 [28,29], we continue in this study to carry out the study of the ionic self-diffusion coefficients of 152 Eu(III) to the investigation of the ionic association phenomenon in the systems {x 1 1,4-dioxane þ (1 0 Àx 1 ) water þ 2 Â 10 À4 mol L À1 Eu(ClO 4 ) 3 } at 298.15 K. Some reasons for this choice are given as follows:…”

Investigation of the Self-Diffusion Coefficients of Trivalent Gd3+ in aqueous solutions: The Effect of Hydrolysis and nitrate ion association

“…In the same context, the stability constant of europium nitrate 22 , berkelium nitrate 23 and lanthanides complex 24 were estimated. In this paper, we will justify our choice of using a pH value of 2.50 in order to avoid hydrolysis of trivalent 4f and 5f ions and to minimize the formation of ion pairs or complexes [6][7][25][26][27][28] . In dilute solutions, the hydrodynamic theory of Onsager may be used for the evaluation and interpretation of transport parameters 29 as a function of the ionic composition of the solution.…”

“…Therefore, it may be argued that 153 Gd (III) and the trivalent actinide ions have essentially the same degree of hydration as a tripositive ion of comparable ionic radii in the absence of hydrolysis, ion pairing or complexing at pH 2.50 31 . For dilute solutions, the variation of D with the square root of the supporting electrolyte solution concentration is not linear 5,7,[25][26][27] . …”

KCl-Induced Phase Separation of 1,4-Dioxane + Water Mixtures Studied by Electrical Conductivity and Refractive Index

“…[14][15][16][17][18][19][20][21][22] Note that progressively introducing electrolytes in water + dioxane mixtures at a low dielectric constant gives evidence of the progressive association of ions pairs. 23 Also, the study of different physicochemical properties in all of the domains of compositions shows the existence of different regions with distinct behaviors. 23 Ion-solvent and solvent-solvent interactions have been investigated.…”