title: Thermodynamical and structural study of protactinium(V) oxalate complexes in solution.
abstract: 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.
authors.affiliation: Université Paris-Sud, Institut de Physique Nucléaire, UMR 8608 Orsay, F-91406, France. mickael.mendes@free.fr
authors.forename: Mickaël
authors.initials: M
authors.lastname: Mendes
authors.forename: Séna
authors.initials: S
authors.lastname: Hamadi
authors.forename: Claire
authors.initials: C
authors.lastname: Le Naour
authors.forename: Jérôme
authors.initials: J
authors.lastname: Roques
authors.forename: Aurélie
authors.initials: A
authors.lastname: Jeanson
authors.forename: Christophe
authors.initials: C
authors.lastname: Den Auwer
authors.forename: Philippe
authors.initials: P
authors.lastname: Moisy
authors.forename: Sylvain
authors.initials: S
authors.lastname: Topin
authors.forename: Jean
authors.initials: J
authors.lastname: Aupiais
authors.forename: Christoph
authors.initials: C
authors.lastname: Hennig
authors.forename: Maria-Vita
authors.initials: MV
authors.lastname: Di Giandomenico
mesh_terms: D019075:Electrophoresis, Capillary; D013058:Mass Spectrometry; D015394:Molecular Structure; D010070:Oxalates / Q000737:chemistry*; D011478:Protactinium / Q000737:chemistry*; D012996:Solutions; D013816:Thermodynamics
chemical_list: D010070:Oxalates; D012996:Solutions; D011478:Protactinium