Thermodynamical and structural study of protactinium(V) oxalate complexes in solution.
The complexation of protactinium(V) by oxalate was studied by X-ray absorption spectroscopy (XAS), density functional theory (DFT) calculations, capillary electrophoresis coupled with inductively coupled plasma mass spectrometry (CE-ICP-MS) and solvent extraction. XAS measurements showed unambiguously the presence of a short single oxo-bond, and the deduced structure agrees with theoretical calculations. CE-ICP-MS results indicated the formation of a highly charged anionic complex. The formation constants of PaO(C(2)O(4))(+), PaO(C(2)O(4))(2)(-), and PaO(C(2)O(4))(3)(3-) were determined from solvent extraction data by using protactinium at tracer scale (C(Pa) < 10(-10) M). Complexation reactions of Pa(V) with oxalate were found to be exothermic with relatively high positive entropic variation.
Mendes
Mickaël
M
Université Paris-Sud, Institut de Physique Nucléaire, UMR 8608 Orsay, F-91406, France. mickael.mendes@free.fr
Hamadi
Séna
S
Le Naour
Claire
C
Roques
Jérôme
J
Jeanson
Aurélie
A
Den Auwer
Christophe
C
Moisy
Philippe
P
Topin
Sylvain
S
Aupiais
Jean
J
Hennig
Christoph
C
Di Giandomenico
Maria-Vita
MV
D019075:Electrophoresis, Capillary; D013058:Mass Spectrometry; D015394:Molecular Structure; D010070:Oxalates / Q000737:chemistry*; D011478:Protactinium / Q000737:chemistry*; D012996:Solutions; D013816:Thermodynamics
D010070:Oxalates; D012996:Solutions; D011478:Protactinium