title: Revealing Disparate Chemistries of Protactinium and Uranium. Synthesis of the Molecular Uranium Tetroxide Anion, UO4.
abstract: The synthesis, reactivity, structures, and bonding in gas-phase binary and complex oxide anion molecules of protactinium and uranium have been studied by experiment and theory. The oxalate ions, AnVO2(C2O4)-, where An = Pa or U, are essentially actinyl ions, AnVO2+, coordinated by an oxalate dianion. Both react with water to yield the pentavalent hydroxides, AnVO(OH)2(C2O4)-. The chemistry of Pa and U becomes divergent for reactions that result in oxidation: whereas PaVIis inaccessible, UVIis very stable. The UVO2(C2O4)-complex exhibits a remarkable spontaneous exothermic replacement of the oxalate ligand by O2to yield UO4-and two CO2molecules. The structure of the uranium tetroxide anion is computed to correspond to distorted uranyl, UVIO22+, coordinated in the equatorial plane by two equivalent O atoms each having formal charges of -1.5 and U-O bond orders intermediate between single and double. The unreactive nature of PaVO2(C2O4)-toward O2is a manifestation of the resistance toward oxidation of PaV, and clearly reveals the disparate chemistries of Pa and U. The uranium tetroxide anion, UO4-, reacts with water to yield UO5H2-. Infrared spectra obtained for UO5H2-confirm the computed lowest-energy structure, UO3(OH)2-.
authors.affiliation: Computational Research Division, Lawrence Berkeley National Laboratory , Berkeley, California 94720, United States.
authors.forename: Wibe A
authors.identifier: http://orcid.org/0000-0002-7114-8315
authors.initials: WA
authors.lastname: de Jong
authors.affiliation: Chemical Sciences Division, Lawrence Berkeley National Laboratory , Berkeley, California 94720, United States.
authors.forename: Phuong D
authors.initials: PD
authors.lastname: Dau
authors.affiliation: Chemical Sciences and Engineering Division, Argonne National Laboratory , Argonne, Illinois 60439, United States.
authors.forename: Richard E
authors.initials: RE
authors.lastname: Wilson
authors.affiliation: Centro de Ciências e Tecnologias Nucleares, Instituto Superior Técnico, Universidade de Lisboa , 2695-066 Bobadela Loures, Portugal.
authors.forename: Joaquim
authors.identifier: http://orcid.org/0000-0001-7580-057X
authors.initials: J
authors.lastname: Marçalo
authors.affiliation: Department of Chemistry and Biochemistry, Duquesne University , Pittsburgh, Pennsylvania 15282, United States.
authors.forename: Michael J
authors.initials: MJ
authors.lastname: Van Stipdonk
authors.affiliation: Department of Physics, Duquesne University , Pittsburgh, Pennsylvania 15282, United States.
authors.forename: Theodore A
authors.identifier: http://orcid.org/0000-0001-5716-1188
authors.initials: TA
authors.lastname: Corcovilos
authors.affiliation: Radboud University , Institute for Molecules and Materials, FELIX Laboratory, Toernooiveld 7c, 6525ED Nijmegen, The Netherlands.
authors.forename: Giel
authors.initials: G
authors.lastname: Berden
authors.affiliation: Radboud University , Institute for Molecules and Materials, FELIX Laboratory, Toernooiveld 7c, 6525ED Nijmegen, The Netherlands.
authors.forename: Jonathan
authors.identifier: http://orcid.org/0000-0001-9537-4117
authors.initials: J
authors.lastname: Martens
authors.affiliation: Radboud University , Institute for Molecules and Materials, FELIX Laboratory, Toernooiveld 7c, 6525ED Nijmegen, The Netherlands.|van 't Hoff Institute for Molecular Sciences, University of Amsterdam , Science Park 904, 1098XH Amsterdam, The Netherlands.
authors.forename: Jos
authors.initials: J
authors.lastname: Oomens
authors.affiliation: Chemical Sciences Division, Lawrence Berkeley National Laboratory , Berkeley, California 94720, United States.
authors.forename: John K
authors.identifier: http://orcid.org/0000-0003-2107-5418
authors.initials: JK
authors.lastname: Gibson