1
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Benjamin SE, LaVerne JA, Sigmon GE, Burns PC. Investigation of Radiation Effects in the Uranyl Mineral Metaschoepite. Inorg Chem 2023. [PMID: 37433111 DOI: 10.1021/acs.inorgchem.3c01337] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 07/13/2023]
Abstract
The effects of water vapor and He ion irradiation on the alteration of particles of the uranyl hydroxide phase metaschoepite, [(UO2)8O2(OH)12](H2O)10, are determined. Raman spectra collected immediately postirradiation revealed the presence of a uranyl oxide phase structurally similar to γ-UO3 or U2O7. Short-term storage postirradiation at elevated relative humidity accelerated formation of the uranyl peroxide phase studtite, [(UO2)(O2)(H2O)2](H2O)2. Experiments examining the degradation of metaschoepite and the hydration of UO3 enabled spectral assignments and identification of reaction pathways. The results provide insights into thermal and radiolytic degradation products in both irradiated uranyl hydroxide phases and uranyl peroxide phases, which follow similar degradation pathways.
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Affiliation(s)
- Savannah E Benjamin
- Department of Chemistry and Biochemistry, University of Notre Dame, Notre Dame, Indiana 46556, United States
| | - Jay A LaVerne
- Radiation Laboratory and Department of Physics and Astronomy, University of Notre Dame, Notre Dame, Indiana 46556, United States
| | - Ginger E Sigmon
- Department of Civil and Environmental Engineering and Earth Sciences, University of Notre Dame, Notre Dame, Indiana 46556, United States
| | - Peter C Burns
- Department of Chemistry and Biochemistry, University of Notre Dame, Notre Dame, Indiana 46556, United States
- Department of Civil and Environmental Engineering and Earth Sciences, University of Notre Dame, Notre Dame, Indiana 46556, United States
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2
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Tse JS, Grant J, Skelton JM, Gillie LJ, Zhu R, Pesce GL, Ball RJ, Parker SC, Molinari M. Location of Artinite (Mg 2CO 3(OH) 2·3H 2O) within the MgO-CO 2-H 2O system using ab initio thermodynamics. Phys Chem Chem Phys 2023. [PMID: 37377444 DOI: 10.1039/d3cp00518f] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/29/2023]
Abstract
The MgO-CO2-H2O system have a variety of important industrial applications including in catalysis, immobilisation of radionuclides and heavy metals, construction, and mineralisation and permanent storage of anthropogenic CO2. Here, we develop a computational approach to generate phase stability plots for the MgO-CO2-H2O system that do not rely on traditional experimental corrections for the solid phases. We compare the predictions made by several dispersion-corrected density-functional theory schemes, and we include the temperature-dependent Gibbs free energy through the quasi-harmonic approximation. We locate the Artinite phase (Mg2CO3(OH)2·3H2O) within the MgO-CO2-H2O phase stability plot, and we demonstrate that this widely-overlooked hydrated and carbonated phase is metastable and can be stabilised by inhibiting the formation of fully-carbonated stable phases. Similar considerations may apply more broadly to other lesser known phases. These findings provide new insight to explain conflicting results from experimental studies, and demonstrate how this phase can potentially be stabilised by optimising the synthesis conditions.
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Affiliation(s)
- Joshua S Tse
- Department of Chemistry, University of Huddersfield, Queensgate, Huddersfield, HD1 3DH, UK.
| | - James Grant
- Department of Chemistry, University of Bath, Claverton Down, Bath, BA2 7AY, UK.
| | - Jonathan M Skelton
- Department of Chemistry, University of Manchester, Oxford Road, Manchester, M13 9PL, UK
| | - Lisa J Gillie
- Department of Chemistry, University of Huddersfield, Queensgate, Huddersfield, HD1 3DH, UK.
| | - Runliang Zhu
- CAS Key Laboratory of Mineralogy and Metallogeny, and Guangdong Provincial Key Laboratory of Mineral Physics and Materials, Guangzhou Institute of Geochemistry, Chinese Academy of Sciences, Guangzhou 510640, P. R. China
| | - Giovanni L Pesce
- Department of Mechanical and Construction Engineering, Northumbria University, Newcastle upon Tyne, NE1 8ST, UK
| | - Richard J Ball
- Department of Architecture and Civil Engineering, University of Bath, Bath, BA2 7AY, UK
| | - Stephen C Parker
- Department of Chemistry, University of Bath, Claverton Down, Bath, BA2 7AY, UK.
| | - Marco Molinari
- Department of Chemistry, University of Huddersfield, Queensgate, Huddersfield, HD1 3DH, UK.
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3
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Cot-Auriol M, Virot M, Micheau C, Dumas T, Le Goff X, Den Auwer C, Diat O, Moisy P, Nikitenko SI. Ultrasonically assisted conversion of uranium trioxide into uranium(vi) intrinsic colloids. Dalton Trans 2021; 50:11498-11511. [PMID: 34346448 DOI: 10.1039/d1dt01609a] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/05/2023]
Abstract
Under oxidizing conditions, the corrosion of spent nuclear fuel may lead to the leaching of radionuclides including soluble uranyl-based species. The speciation of the generated chemical forms is complex and the related potential formation of colloidal species appears surprisingly poorly reported in the literature. Their formation could however contribute significantly to the mobility of radionuclides in the environment. A better knowledge in the speciation and reactivity of these species appears particularly relevant. This study describes the preparation and characterization of intrinsic uranium(vi) colloids from amorphous and crystalline UO3 in pure water assisted by 20 kHz ultrasound. In the presence of carbon monoxide preventing the sonochemical formation of hydrogen peroxide, ultrasonic treatment boosts the conversion of UO3 powder into (meta-)schoepite precipitates and yields very stable and notably concentrated uranium(vi) nanoparticles in the liquid phase. Using HR-TEM, SAXS and XAS techniques, we confirmed that the colloidal suspension is composed of quasi-spherical nanoparticles measuring ca. 3.8 ± 0.3 nm and exhibiting a schoepite-like crystallographic structure. The proposed method demonstrates the possible formation of environmentally relevant U(vi) colloidal nanoparticles appearing particularly interesting for the preparation of reference systems in the absence of added ions and capping agents.
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4
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Pandelus SB, Kennedy BJ, Murphy G, Brand HE, Keegan E, Pring A, Popelka-Filcoff RS. Phase Analysis of Australian Uranium Ore Concentrates Determined by Variable Temperature Synchrotron Powder X-ray Diffraction. Inorg Chem 2021; 60:11569-11578. [PMID: 34293259 DOI: 10.1021/acs.inorgchem.1c01562] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
The chemical speciation of uranium oxides is sensitive to the provenance of the samples and their storage conditions. Here, we use diffraction methods to characterize the phases found in three aged (>10 years) uranium ore concentrates of different origins as well as in situ analysis of the thermally induced structural transitions of these materials. The structures of the crystalline phases found in the three samples have been refined, using high-resolution synchrotron X-ray diffraction data. Rietveld analysis of the samples from the Olympic Dam and Ranger uranium mines has revealed the presence of crystalline α-UO2(OH)2, together with metaschoepite (UO2)4O(OH)6·5H2O, in the aged U3O8 samples, and it is speculated that this forms as a consequence of the corrosion of U3O8 in the presence of metaschoepite. The third sample, from the Beverley uranium mine, contains the peroxide [UO2(η2-O2)(H2O)2] (metastudtite) together with α-UO2(OH)2 and metaschoepite. A core-shell model is proposed to account for the broadening of the diffraction peaks of the U3O8 evident in the samples.
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Affiliation(s)
- Samantha B Pandelus
- College of Science and Engineering, Flinders University, Adelaide, South Australia 5001, Australia
| | - Brendan J Kennedy
- School of Chemistry, The University of Sydney, Sydney, New South Wales 2006, Australia
| | - Gabriel Murphy
- School of Chemistry, The University of Sydney, Sydney, New South Wales 2006, Australia.,ANSTO, Lucas Heights, Sydney, New South Wales 2234, Australia
| | - Helen E Brand
- Australian Synchrotron, 800 Blackburn Road, Clayton, Victoria 3168, Australia
| | | | - Allan Pring
- College of Science and Engineering, Flinders University, Adelaide, South Australia 5001, Australia.,School of Physical Sciences, University of Adelaide, Adelaide, South Australia 5005, Australia
| | - Rachel S Popelka-Filcoff
- College of Science and Engineering, Flinders University, Adelaide, South Australia 5001, Australia.,School of Geography, Earth and Atmospheric Sciences, University of Melbourne, Parkville, Victoria 3010, Australia
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5
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Abstract
AbstractStudtite is known to exist at the back-end of the nuclear fuel cycle as an intermediate phase formed in the reprocessing of spent nuclear fuel. In the thermal decomposition of studtite, an amorphous phase is obtained at calcination temperatures between 200 and 500 °C. This amorphous compound, referred to elsewhere in the literature as U2O7, has been characterised by analytical spectroscopic methods. The local structure of the amorphous compound has been found to contain uranyl bonding by X-ray absorption near edge (XANES), Fourier transform infrared and Raman spectroscopy. Changes in bond distances in the uranyl group are discussed with respect to studtite calcination temperature. The reaction of the amorphous compound with water to form metaschoepite is also discussed and compared with the structure of schoepite and metaschoepite by X-ray diffraction. A novel schematic reaction mechanism for the thermal decomposition of studtite is proposed.
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6
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Spano TL, Shields AE, Barth BS, Gruidl JD, Niedziela JL, Kapsimalis RJ, Miskowiec A. Computationally Guided Investigation of the Optical Spectra of Pure β-UO3. Inorg Chem 2020; 59:11481-11492. [DOI: 10.1021/acs.inorgchem.0c01279] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Affiliation(s)
- Tyler L. Spano
- Nuclear Nonproliferation Division, Oak Ridge National Laboratory, 1 Bethel Valley Road, Oak Ridge, Tennessee 37831, United States
| | - Ashley E. Shields
- Nuclear Nonproliferation Division, Oak Ridge National Laboratory, 1 Bethel Valley Road, Oak Ridge, Tennessee 37831, United States
| | - Brianna S. Barth
- Nuclear Nonproliferation Division, Oak Ridge National Laboratory, 1 Bethel Valley Road, Oak Ridge, Tennessee 37831, United States
- University of Texas at Austin, Department of Chemistry, 105 East 24th Street, Austin, Texas 78712, United States
| | - Jeremiah D. Gruidl
- Nuclear Nonproliferation Division, Oak Ridge National Laboratory, 1 Bethel Valley Road, Oak Ridge, Tennessee 37831, United States
| | - Jennifer L. Niedziela
- Nuclear Nonproliferation Division, Oak Ridge National Laboratory, 1 Bethel Valley Road, Oak Ridge, Tennessee 37831, United States
| | - Roger J. Kapsimalis
- Nuclear Nonproliferation Division, Oak Ridge National Laboratory, 1 Bethel Valley Road, Oak Ridge, Tennessee 37831, United States
| | - Andrew Miskowiec
- Nuclear Nonproliferation Division, Oak Ridge National Laboratory, 1 Bethel Valley Road, Oak Ridge, Tennessee 37831, United States
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7
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Koroglu B, Dai Z, Finko M, Armstrong MR, Crowhurst JC, Curreli D, Weisz DG, Radousky HB, Knight KB, Rose TP. Experimental Investigation of Uranium Volatility during Vapor Condensation. Anal Chem 2020; 92:6437-6445. [PMID: 32233449 DOI: 10.1021/acs.analchem.9b05562] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/01/2023]
Abstract
The predictive models that describe the fate and transport of radioactive materials in the atmosphere following a nuclear incident (explosion or reactor accident) assume that uranium-bearing particulates would attain chemical equilibrium during vapor condensation. In this study, we show that kinetically driven processes in a system of rapidly decreasing temperature can result in substantial deviations from chemical equilibrium. This can cause uranium to condense out in oxidation states (e.g., UO3 vs UO2) that have different vapor pressures, significantly affecting uranium transport. To demonstrate this, we synthesized uranium oxide nanoparticles using a flow reactor under controlled conditions of temperature, pressure, and oxygen concentration. The atomized chemical reactants passing through an inductively coupled plasma cool from ∼5000 to 1000 K within milliseconds and form nanoparticles inside a flow reactor. The ex situ analysis of particulates by transmission electron microscopy revealed 2-10 nm crystallites of fcc-UO2 or α-UO3 depending on the amount of oxygen in the system. α-UO3 is the least thermodynamically preferred polymorph of UO3. The absence of stable uranium oxides with intermediate stoichiometries (e.g., U3O8) and sensitivity of the uranium oxidation states to local redox conditions highlight the importance of in situ measurements at high temperatures. Therefore, we developed a laser-based diagnostic to detect uranium oxide particles as they are formed inside the flow reactor. Our in situ measurements allowed us to quantify the changes in the number densities of the uranium oxide nanoparticles (e.g., UO3) as a function of oxygen gas concentration. Our results indicate that uranium can prefer to be in metastable crystal forms (i.e., α-UO3) that have higher vapor pressures than the refractory form (i.e., UO2) depending on the oxygen abundance in the surrounding environment. This demonstrates that the equilibrium processes may not dominate during rapid condensation processes, and thus kinetic models are required to fully describe uranium transport subsequent to nuclear incidents.
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Affiliation(s)
- Batikan Koroglu
- Physical and Life Sciences, Lawrence Livermore National Laboratory, Livermore, California 94550, United States
| | - Zurong Dai
- Physical and Life Sciences, Lawrence Livermore National Laboratory, Livermore, California 94550, United States
| | - Mikhail Finko
- Nuclear Plasma and Radiological Engineering, College of Engineering, University of Illinois at Urbana-Champagne, Urbana, Illinois 61801, United States
| | - Michael R Armstrong
- Physical and Life Sciences, Lawrence Livermore National Laboratory, Livermore, California 94550, United States
| | - Jonathan C Crowhurst
- Physical and Life Sciences, Lawrence Livermore National Laboratory, Livermore, California 94550, United States
| | - Davide Curreli
- Nuclear Plasma and Radiological Engineering, College of Engineering, University of Illinois at Urbana-Champagne, Urbana, Illinois 61801, United States
| | - David G Weisz
- Physical and Life Sciences, Lawrence Livermore National Laboratory, Livermore, California 94550, United States
| | - Harry B Radousky
- Physical and Life Sciences, Lawrence Livermore National Laboratory, Livermore, California 94550, United States
| | - Kim B Knight
- Physical and Life Sciences, Lawrence Livermore National Laboratory, Livermore, California 94550, United States
| | - Timothy P Rose
- Physical and Life Sciences, Lawrence Livermore National Laboratory, Livermore, California 94550, United States
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8
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Wilkerson MP, Hernandez SC, Mullen WT, Nelson AT, Pugmire AL, Scott BL, Sooby ES, Tamasi AL, Wagner GL, Walensky JR. Hydration of α-UO3 following storage under controlled conditions of temperature and relative humidity. Dalton Trans 2020; 49:10452-10462. [DOI: 10.1039/d0dt01852j] [Citation(s) in RCA: 16] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
Experimental measurements and theoretical evaluation of changes in chemical speciation of α-UO3 using XRD, EXAFS, TGA, and DFT calculations.
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Affiliation(s)
| | | | | | | | | | | | | | - Alison L. Tamasi
- Los Alamos National Laboratory
- Los Alamos
- USA
- Department of Chemistry
- University of Missouri-Columbia
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9
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Liu T, Li S, Gao T, Ao B. Theoretical prediction of some layered Pa2O5 phases: structure and properties. RSC Adv 2019; 9:31398-31405. [PMID: 35527940 PMCID: PMC9072604 DOI: 10.1039/c9ra06735c] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/26/2019] [Accepted: 09/19/2019] [Indexed: 11/21/2022] Open
Abstract
Density functional theory (DFT) was used to predict and study protactinium pentoxide (Pa2O5), which presents a fluorite and layered protactinium oxide-type structure. Although the layered structure has been observed with the isostructural transition Nb and Ta metal pentoxides experimentally, the detailed structure and properties of the layered Pa2O5 are not clear and understandable. Our theoretical prediction explored some possible stable structures of the Pa2O5 stoichiometry according to the existing M2O5 structures (where M is an actinide Np or transition Nb, Ta, and V metal) and replacing the M ions with protactinium ions. The structural, mechanical, thermodynamic and electronic properties including lattice parameters, bulk moduli, elastic constants, entropy and band gaps were predicted for all the simulated structures. Pa2O5 in the β-V2O5 structure was found to be a competitive structure in terms of stability, whereas Pa2O5 in the ζ-Nb2O5 structure was found to be the most stable overall. This is consistent with Sellers's experimental observations. In particular, Pa2O5 in the ζ-Nb2O5 structure is predicted to be charge-transfer insulators. Furthermore, we predict that ζ-Nb2O5-structured Pa2O5 is the most thermodynamically stable under ambient conditions and pressure. Density functional theory (DFT) was used to predict and study protactinium pentoxide (Pa2O5), which presents a fluorite and layered protactinium oxide-type structure.![]()
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Affiliation(s)
- Tao Liu
- Institute of Atomic and Molecular Physics
- Sichuan University
- Chengdu
- China
- School of Electronic and Communication Engineering
| | - Shichang Li
- Institute of Atomic and Molecular Physics
- Sichuan University
- Chengdu
- China
| | - Tao Gao
- Institute of Atomic and Molecular Physics
- Sichuan University
- Chengdu
- China
| | - Bingyun Ao
- Science and Technology on Surface Physics and Chemistry Laboratory
- Jiangyou
- China
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10
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Lu G, Haes AJ, Forbes TZ. Detection and identification of solids, surfaces, and solutions of uranium using vibrational spectroscopy. Coord Chem Rev 2018; 374:314-344. [PMID: 30713345 PMCID: PMC6358285 DOI: 10.1016/j.ccr.2018.07.010] [Citation(s) in RCA: 82] [Impact Index Per Article: 13.7] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022]
Abstract
The purpose of this review is to provide an overview of uranium speciation using vibrational spectroscopy methods including Raman and IR. Uranium is a naturally occurring, radioactive element that is utilized in the nuclear energy and national security sectors. Fundamental uranium chemistry is also an active area of investigation due to ongoing questions regarding the participation of 5f orbitals in bonding, variation in oxidation states and coordination environments, and unique chemical and physical properties. Importantly, uranium speciation affects fate and transportation in the environment, influences bioavailability and toxicity to human health, controls separation processes for nuclear waste, and impacts isotopic partitioning and geochronological dating. This review article provides a thorough discussion of the vibrational modes for U(IV), U(V), and U(VI) and applications of infrared absorption and Raman scattering spectroscopies in the identification and detection of both naturally occurring and synthetic uranium species in solid and solution states. The vibrational frequencies of the uranyl moiety, including both symmetric and asymmetric stretches are sensitive to the coordinating ligands and used to identify individual species in water, organic solvents, and ionic liquids or on the surface of materials. Additionally, vibrational spectroscopy allows for the in situ detection and real-time monitoring of chemical reactions involving uranium. Finally, techniques to enhance uranium species signals with vibrational modes are discussed to expand the application of vibrational spectroscopy to biological, environmental, inorganic, and materials scientists and engineers.
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Affiliation(s)
- Grace Lu
- Department of Chemistry, University of Iowa, Iowa City, IA 52242, United States
| | - Amanda J. Haes
- Department of Chemistry, University of Iowa, Iowa City, IA 52242, United States
| | - Tori Z. Forbes
- Department of Chemistry, University of Iowa, Iowa City, IA 52242, United States
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11
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Moore EE, Kocevski V, Juillerat CA, Morrison G, Zhao M, Brinkman KS, Loye HCZ, Besmann TM. Understanding the Stability of Salt-Inclusion Phases for Nuclear Waste-forms through Volume-based Thermodynamics. Sci Rep 2018; 8:15294. [PMID: 30333564 PMCID: PMC6193005 DOI: 10.1038/s41598-018-32903-3] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/26/2018] [Accepted: 09/18/2018] [Indexed: 11/18/2022] Open
Abstract
Formation enthalpies and Gibbs energies of actinide and rare-earth containing SIMs with silicate and germanate frameworks are reported. Volume-based thermodynamics (VBT) techniques complemented by density functional theory (DFT) were adapted and applied to these complex structures. VBT and DFT results were in closest agreement for the smaller framework silicate structure, whereas DFT in general predicts less negative enthalpies across all SIMs, regardless of framework type. Both methods predict the rare-earth silicates to be the most stable of the comparable structures calculated, with VBT results being in good agreement with the limited experimental values available from drop solution calorimetry.
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Affiliation(s)
- Emily E Moore
- Nuclear Engineering Program, Department of Mechanical Engineering, University of South Carolina, Columbia, SC, 29208, USA.
| | - Vancho Kocevski
- Nuclear Engineering Program, Department of Mechanical Engineering, University of South Carolina, Columbia, SC, 29208, USA
| | | | - Gregory Morrison
- Department of Chemistry, University of South Carolina, Columbia, SC, 29208, USA
| | - Mingyang Zhao
- Department of Materials Science and Engineering, Clemson University, Clemson, SC, 29634, USA
| | - Kyle S Brinkman
- Department of Materials Science and Engineering, Clemson University, Clemson, SC, 29634, USA
| | | | - Theodore M Besmann
- Nuclear Engineering Program, Department of Mechanical Engineering, University of South Carolina, Columbia, SC, 29208, USA
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12
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Juillerat CA, Moore EE, Kocevski V, Besmann T, zur Loye HC. A Family of Layered Phosphates Crystallizing in a Rare Geometrical Isomer of the Phosphuranylite Topology: Synthesis, Characterization, and Computational Modeling of A4[(UO2)3O2(PO4)2] (A = Alkali Metal) Exhibiting Intralayer Ion Exchange. Inorg Chem 2018; 57:4726-4738. [DOI: 10.1021/acs.inorgchem.8b00434] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Affiliation(s)
- Christian A. Juillerat
- The Center for Hierarchical Wasteform Materials, University of South Carolina, Columbia, South Carolina 29208, United States
| | - Emily E. Moore
- The Center for Hierarchical Wasteform Materials, University of South Carolina, Columbia, South Carolina 29208, United States
| | - Vancho Kocevski
- The Center for Hierarchical Wasteform Materials, University of South Carolina, Columbia, South Carolina 29208, United States
| | - Theodore Besmann
- The Center for Hierarchical Wasteform Materials, University of South Carolina, Columbia, South Carolina 29208, United States
| | - Hans-Conrad zur Loye
- The Center for Hierarchical Wasteform Materials, University of South Carolina, Columbia, South Carolina 29208, United States
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13
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Flores LA, Murphy JG, Copeland WB, Dixon DA. Reaction of CO2 with UO3 Nanoclusters. J Phys Chem A 2017; 121:8518-8524. [DOI: 10.1021/acs.jpca.7b09107] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Affiliation(s)
- Luis A. Flores
- Department of Chemistry, The University of Alabama, Shelby Hall, Tuscaloosa, Alabama 35487-0336, United States
| | - Julia G. Murphy
- Department of Chemistry, The University of Alabama, Shelby Hall, Tuscaloosa, Alabama 35487-0336, United States
| | - William B. Copeland
- Department of Chemistry, The University of Alabama, Shelby Hall, Tuscaloosa, Alabama 35487-0336, United States
| | - David A. Dixon
- Department of Chemistry, The University of Alabama, Shelby Hall, Tuscaloosa, Alabama 35487-0336, United States
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14
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Molinari M, Brincat NA, Allen GC, Parker SC. Structure and Properties of Some Layered U2O5 Phases: A Density Functional Theory Study. Inorg Chem 2017; 56:4469-4474. [DOI: 10.1021/acs.inorgchem.7b00014] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Affiliation(s)
- Marco Molinari
- Department of Chemistry, University of Bath, Claverton Down, Bath BA2
7AY, United Kingdom
- Department of Chemistry, University of Huddersfield, Queensgate, Huddersfield HD1 3DH, United Kingdom
| | - Nicholas A. Brincat
- Department of Chemistry, University of Bath, Claverton Down, Bath BA2
7AY, United Kingdom
- AWE Public Limited Company, Aldermaston, Reading RG7 4PR, United Kingdom
| | - Geoffrey C. Allen
- AWE Public Limited Company, Aldermaston, Reading RG7 4PR, United Kingdom
- Interface
Analysis Center, University of Bristol, Bristol, United Kingdom
| | - Stephen C. Parker
- Department of Chemistry, University of Bath, Claverton Down, Bath BA2
7AY, United Kingdom
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15
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Desgranges L, Ma Y, Garcia P, Baldinozzi G, Siméone D, Fischer HE. What Is the Actual Local Crystalline Structure of Uranium Dioxide, UO 2? A New Perspective for the Most Used Nuclear Fuel. Inorg Chem 2016; 56:321-326. [PMID: 27977186 DOI: 10.1021/acs.inorgchem.6b02111] [Citation(s) in RCA: 37] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
Up to now, uranium dioxide, the most used nuclear fuel, was said to have a Fm3̅m crystalline structure from 30 to 3000 K, and its behavior was modeled under this assumption. However, recently X-ray diffraction experiments provided atomic pair-distribution functions of UO2, in which UO distance was shorter than the expected value for the Fm3̅m space group. Here we show neutron diffraction results that confirm this shorter UO bond, and we also modeled the corresponding pair-distribution function showing that UO2 has a local Pa3̅ symmetry. The existence of a local lower symmetry in UO2 could explain some unexpected properties of UO2 that would justify UO2 modeling to be reassessed. It also deserves more study from an academic point of view because of its good thermoelectric properties that may originate from its particular crystalline structure.
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Affiliation(s)
- L Desgranges
- CEA, DEN, DEC F-13108 Saint Paul lez Durance Cedex, France
| | - Y Ma
- CEA, DEN, DEC F-13108 Saint Paul lez Durance Cedex, France
| | - Ph Garcia
- CEA, DEN, DEC F-13108 Saint Paul lez Durance Cedex, France
| | - G Baldinozzi
- SPMS, LRC Carmen, CNRS Centrale Supélec , 92295 Châtenay-Malabry, France.,CEA, DEN, DMN F-91191 Gif-sur-Yvette Cedex, France
| | - D Siméone
- SPMS, LRC Carmen, CNRS Centrale Supélec , 92295 Châtenay-Malabry, France.,CEA, DEN, DMN F-91191 Gif-sur-Yvette Cedex, France
| | - H E Fischer
- Institut Laue-Langevin , 6 rue Jules Horowitz, B.P. 156, 38042 Grenoble Cedex, France
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16
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Flitcroft JM, Molinari M, Brincat NA, Storr MT, Parker SC. Hydride ion formation in stoichiometric UO2. Chem Commun (Camb) 2015; 51:16209-12. [DOI: 10.1039/c5cc04799d] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
We investigated hydrogen solubility in UO2 using DFT and predicted that hydrogen species energetically prefers to exist as a hydride ion rather than a proton in a hydroxyl group and on diffusion hydrogen's charge state will change.
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Affiliation(s)
| | - M. Molinari
- Department of Chemistry
- University of Bath
- Bath
- UK
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17
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Brincat NA, Parker SC, Molinari M, Allen GC, Storr MT. Density functional theory investigation of the layered uranium oxides U3O8 and U2O5. Dalton Trans 2015; 44:2613-22. [DOI: 10.1039/c4dt02493a] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
New predictions of structural, electronic and mechanical properties of layered uranium oxides using DFT + U calculations.
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