Investigation of the polymorphs and hydrolysis of uranium trioxide

Sweet, Lucas E.; Blake, Thomas A.; Henager, Charles H.; Hu, Sanmei; Johnson, Timothy J.; Meier, David E.; Peper, Shane M.; Schwantes, Jon M.

doi:10.1007/s10967-012-2063-9

Cited by 46 publications

(71 citation statements)

References 25 publications

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“…The Raman spectrum of γ-UO3 was observed by Armstrong et al 51 and Sweet et al [1][2] . A strong band was observed at 766 cm -1 , a medium strength band at 335 cm -1 , and weaker bands appear at 690, 483, 235, 103 and 51 cm -1 .…”

Section: Introductionmentioning

confidence: 84%

“…5 Since production processes of uranium trioxide result in mixtures of the different polymorphic phases and small changes in the conditions of these processes affect the phase genesis giving rise to differences in the final products, the study of UO3 system components is very useful in order to understand the process history. Sweet et al [1][2] studied this system through the combined application of traditional (X-Ray diffraction) and a variety of optical techniques. These authors developed Raman and fluorescence spectroscopic libraries for pure and mixed polymorphic forms of UO3 in addition to the common hydrolysis products of UO3.…”

Section: Introductionmentioning

confidence: 99%

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Density Functional Theory Study of the Thermodynamic and Raman Vibrational Properties of γ-UO₃ Polymorph

et al. 2017

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Gamma uranium trioxide, γ-UO3, is one of the most important polymorphs in uranium trioxide system which is common throughout the nuclear fuel cycle and used industrially in the reprocessing of nuclear fuel and uranium enrichment. In this work, a detailed theoretical solid-state density functional theory study of this material was carried out. The computed lattice parameters, bond lengths, bond angles and X-Ray powder pattern were found in very good agreement with their experimental counterparts determined by X-Ray diffraction. The equation of state of γ-UO3 was obtained and, therefore, the values of the bulk modulus and its derivatives, for which there are not experimental data to compare with, were predicted. The computed bulk modulus differs from that of a previous density functional theory calculation by only 4.4%. The thermodynamic properties of this material, including heat capacity, entropy, enthalpy, free energy and Debye temperature were also determined as a function of temperature in the range 0-1000 K. The computed low-and high-temperature thermodynamic functions are in excellent agreement with the experimental ones determined from calorimetric measurements. At ambient temperature, the computed values of heat capacity, entropy, enthalpy and free energy differ from the experimental values by 5.3, 3.3, 3.9 and 2.6%, respectively. Finally, the Raman spectrum was determined and compared with the experimental one and was found to be in good agreement. A normal mode analysis of the theoretical spectra was carried out and used in order to resolve the uncertainty of the assignment in the observed Raman bands. The assignment permits to attribute the different bands to vibrations localized in the different distorted octahedra associated to the two non-equivalent uranium atom types present in the structure of γ-UO3.

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Section: Introductionmentioning

confidence: 84%

Section: Introductionmentioning

confidence: 99%

Density Functional Theory Study of the Thermodynamic and Raman Vibrational Properties of γ-UO₃ Polymorph

et al. 2017

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“…The simplest U(VI) oxide is UO 3 , which can form at least seven different crystalline forms depending on the identity of the starting material [78,79]. Of the seven polymorphs, γ-UO 3 is the most studied, with major Raman modes located at 767, 484, and 399 cm −1 [79]. DFT calculations combined with experimental results provide structural details of the gamma phase and indicate that there are two crystallographically unique U atoms [78,80].…”

Section: Chemical and Structural Elucidation Of Uranium Solid-state Cmentioning

confidence: 99%

Detection and identification of solids, surfaces, and solutions of uranium using vibrational spectroscopy

Haes

Forbes

2018

Coordination Chemistry Reviews

133

128

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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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“…29 No Raman signals for the T 2g mode of UO 2 (445 cm À1 ) and symmetric stretching vibration mode of the uranyl group UO 2 2+ (840 cm À1 ) typical of uranium phases were detected. 30,31 This indicates U was likely incorporated into the TiO 2 matrix. The Raman peak centered at 145 cm À1 is shown in Fig.…”

Section: Raman Spectroscopymentioning

confidence: 99%

Photocatalytic decomposition of Rhodamine B on uranium-doped mesoporous titanium dioxide

et al. 2017

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Investigation of the polymorphs and hydrolysis of uranium trioxide

Cited by 46 publications

References 25 publications

Density Functional Theory Study of the Thermodynamic and Raman Vibrational Properties of γ-UO₃ Polymorph

Density Functional Theory Study of the Thermodynamic and Raman Vibrational Properties of γ-UO₃ Polymorph

Detection and identification of solids, surfaces, and solutions of uranium using vibrational spectroscopy

Photocatalytic decomposition of Rhodamine B on uranium-doped mesoporous titanium dioxide

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Investigation of the polymorphs and hydrolysis of uranium trioxide

Cited by 46 publications

References 25 publications

Density Functional Theory Study of the Thermodynamic and Raman Vibrational Properties of γ-UO3 Polymorph

Density Functional Theory Study of the Thermodynamic and Raman Vibrational Properties of γ-UO3 Polymorph

Detection and identification of solids, surfaces, and solutions of uranium using vibrational spectroscopy

Photocatalytic decomposition of Rhodamine B on uranium-doped mesoporous titanium dioxide

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Density Functional Theory Study of the Thermodynamic and Raman Vibrational Properties of γ-UO₃ Polymorph

Density Functional Theory Study of the Thermodynamic and Raman Vibrational Properties of γ-UO₃ Polymorph