Uranium Oxidation State Finally Revealed

Physics ◽  
2013 ◽  
Vol 6 ◽  
Author(s):  
Anonymous
Keyword(s):  
Oxidation State ◽  
Uranium Oxidation

scholarly journals Changes in u(VI) SPeciation Upon Sorption onto Montmorillonite from Aqueous and Organic Solutions

1991 ◽  
Vol 257 ◽  
Author(s):  
Catherine Chisholm-Brause ◽  
Steven D. Conradson ◽  
P. Gary Eller ◽  
David E. Morris
Keyword(s):  
Oxidation State ◽  
Aqueous Systems ◽  
X Ray ◽  
Ph Values ◽  
Uranium Oxidation ◽  
Organic Solutions ◽  
X Ray Absorption ◽  
Hydrolysis Of ◽  
Uranium Species ◽  
Lines Of Evidence

ABSTRACTThe speciation of UO22+ and UO22+/ TBP mixtures has been investigated in solution and intercalated with the reference smectite clay SAz-1 using x-ray absorption, Raman, andluminescence spectroscopies. Neither aquated UO22+ nor its TBP complex undergoes any detectable changes in uranium oxidation state on intercalation. Further, at the pH values employed in this work, there is no evidence for hydrolysis of the uranium species to generate dimeric or higher order uranium oligomers. However, we do find indications that the structures of the solution complexes are altered on intercalation, particularly for the UO22+TBP system and for more dilute UO22+/aqueous systems. In addition, several lines of evidence suggest that, at the loading levels used in this study, the uranyl species is interacting with two or more spectroscopically distinguishable sites on SAz-1.

Uranium oxidation state and related variations in geochemistry of phosphorites from the Negev (southern Israel)

2002 ◽  
Vol 189 (3-4) ◽  
pp. 213-230 ◽  
Author(s):  
David Soudry ◽  
Sarah Ehrlich ◽  
Olga Yoffe ◽  
Yaacov Nathan
Keyword(s):  
Oxidation State ◽  
Uranium Oxidation

Characterization and Dissolution of ZrTh3UO10 and Th3UO8 Ceramics

2002 ◽  
Vol 713 ◽  
Author(s):  
Gini Curran ◽  
Yoann Sevestre ◽  
Wendy Rattray ◽  
Patrick G. Allen ◽  
Ken R. Czerwinski
Keyword(s):  
Oxidation State ◽  
X Ray Diffraction ◽  
X Ray ◽  
Uranium Oxidation ◽  
Absorption Studies ◽  
The Matrix ◽  
Microscopy Techniques ◽  
Long Term Behavior ◽  
Electron Energy Loss ◽  
X Ray Absorption

ABSTRACTThoria-urania-zirconia ceramics were studied in order to investigate the long-term behavior of potential thorium fuels in a repository environment. The ceramics were prepared by coprecipitation of the metal salts. Zirconia was added to determine if further stabilization against dissolution of the thoria-urania system could be achieved. In addition, 0.5 wt% MgO was added to some samples to increase stability and density. The inclusion of Zr in the ceramics did not dramatically decrease the leaching of thorium from the matrix.Material properties of the ceramic were analyzed using electron microscopy techniques such as Energy Dispersive X-ray (EDX) analysis and Electron Energy Loss Spectroscopy (EELS). X-ray diffraction and synchrotron-based x-ray absorption studies including extended xray fine structure (EXAFS) and x-ray absorption near edge spectroscopy (XANES) were also used to reveal elements of the phase structure and chemistry of the ceramics. X-ray diffraction (XRD) and EDX show that these ceramics separate into a zirconium-based phase and an actinide-based phase with low mutual affinity of thorium and zirconium, as well as partial solubilization of uranium in zirconium. The comparison of EELS spectra collected for the ceramics with spectra collected for UO2 and U3O8 reference materials also allow the assessment of uranium oxidation state independently in the two separate phases. Assessment of the bulk oxidation state using XANES correlated well with the EELS analysis. Interatomic distances and the bulk crystal structure were determined using EXAFS.

Complex XPS Spectra Structure of U5p Electrons and the Uranium Oxidation State

2020 ◽  
Vol 62 (5) ◽  
pp. 608-616
Author(s):  
K. I. Maslakov ◽  
V. G. Yarzhemsky ◽  
Yu. A. Teterin ◽  
A. Yu. Teterin ◽  
K. E. Ivanov
Keyword(s):  
Oxidation State ◽  
Xps Spectra ◽  
Uranium Oxidation

Theoretical investigation of U(i) arene complexes: is the elusive monovalent oxidation state accessible?

2019 ◽  
Vol 43 (3) ◽  
pp. 1469-1477 ◽  
Author(s):  
Jia-Nan Tian ◽  
Ming Zheng ◽  
Li Li ◽  
Georg Schreckenbach ◽  
Yuan-Ru Guo ◽  
...  
Keyword(s):  
Oxidation State ◽  
Theoretical Investigation ◽  
Arene Complexes ◽  
Relativistic Dft ◽  
Uranium Oxidation

With the goal to extend the uranium oxidation state, relativistic DFT unravels an energetically favored U(i) complex of a heterocalix[4]arene.

Oxygen Lattice Distortions and U Oxidation State in UO2+x Fluorite Structures

2008 ◽  
Vol 1124 ◽  
Author(s):  
Lionel Desgranges ◽  
Gianguido Baldinozzi
Keyword(s):  
Oxidation State ◽  
Structural Changes ◽  
Lattice Parameter ◽  
Cationic Sublattice ◽  
Ionic Radii ◽  
Uranium Oxidation ◽  
Vegard’S Law ◽  
Wide Range ◽  
Lattice Distortions ◽  
The Ideal

AbstractThe structural changes induced by the changes of the uranium oxidation state in the ideal fluorite lattice of pure UO2 are discussed. Experimental results evidence strong distortions of the oxygen sub-lattice due to dynamic (at high temperature) or static (at low temperature) fluctuations of the local charges in the cationic sublattice. These changes in the oxidation state are often described using the Vegard’s law because a linear dependence of lattice parameter is observed over a wide range of compositions. Nevertheless, an ideal solid solution model cannot explain this behavior where the elastic effects are directly related to the ionic radii of the cations. Strong evidence is provided that enthalpy effects are relevant in these systems and that they are directly associated with the local structural changes observed during neutron scattering experiments.

Evaluating Chemical Extraction Techniques for the Determination of Uranium Oxidation State in Reduced Aquifer Sediments

2013 ◽  
Vol 47 (16) ◽  
pp. 9225-9232 ◽  
Author(s):  
Deborah L. Stoliker ◽  
Kate M. Campbell ◽  
Patricia M. Fox ◽  
David M. Singer ◽  
Nazila Kaviani ◽  
...  
Keyword(s):  
Oxidation State ◽  
Chemical Extraction ◽  
Extraction Techniques ◽  
Uranium Oxidation ◽  
Aquifer Sediments

Chromium oxidation state mapping in human cells

2003 ◽  
Vol 104 ◽  
pp. 289-292 ◽  
Author(s):  
R. Ortega ◽  
B. Fayard ◽  
M. Salomé ◽  
G. Devès ◽  
J. Susini
Keyword(s):  
Oxidation State ◽  
Human Cells ◽  
Chromium Oxidation
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