Determination of formation constants of hydroxo and carbonate complexes of Pr(3+) in 2 M NaCl at 303 K.
The hydrolysis of praseodymium III in 2 M sodium chloride at 303 K was studied. Two methods were used: pH titration followed by a computational refinement and solvent extraction in the presence of a competitive ligand. The hydrolysis constants obtained by pH titration were: logbeta(1,H)=-7.68+/-0.07, logbeta(1,2H)=-15.10+/-0.03, and beta(1,3H)=-23.80+/-0.04. The stability constants of praseodymium carbonate complexes were determined by pH titration as well and were: logbeta(1,CO(2-)(3))=5.94+/-0.08 and logbeta(1,2CO(2-)(3))=11.15+/-0.15. Praseodymium carbonate species were taken into consideration for calculating the first hydrolysis constants by the solvent extraction method and the value obtained was: logbeta(1,H)=-7.69+/-0.27. The values for logbeta(1,H) attained by both methods are the same. The species-distribution diagram was obtained from the stability constants of praseodymium carbonate complexes and hydrolysis products in the conditions of the present work.
López-González
H
H
Instituto Nacional de Investigaciones Nucleares, Depto. de Quimica, Apdo. Postal 18-1027, 11801 Mexico, DF, Mexico; Universidad Autónoma Metropolitana-Iztapalapa, Area de Electroquimica, Apdo. Postal 55-534, 09340 Mexico, DF, Mexico.
Jiménez-Reyes
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M
Rojas-Hernández
A
A
Solache-Ríos
M
M