19525-15-6Relevant articles and documents
Revealing Disparate Chemistries of Protactinium and Uranium. Synthesis of the Molecular Uranium Tetroxide Anion, UO4-
De Jong, Wibe A.,Dau, Phuong D.,Wilson, Richard E.,Mar?alo, Joaquim,Van Stipdonk, Michael J.,Corcovilos, Theodore A.,Berden, Giel,Martens, Jonathan,Oomens, Jos,Gibson, John K.
, p. 3686 - 3694 (2017/03/24)
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 PaVI is inaccessible, UVI is very stable. The UVO2(C2O4)? complex exhibits a remarkable spontaneous exothermic replacement of the oxalate ligand by O2 to yield UO4- and two CO2 molecules. 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 O2 is 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-
