Theoretical Assignment of Oxidation State of Uranium in Binary, Ternary, and Quaternary Tellurides

Qian, Shijun; Qiu, Ruizhi; Tang, Jun; Chen, Jinfan; Liu, Pengchuang; Ao, Bingyun

doi:10.1021/acs.jpcc.0c09298

Cited by 3 publications

(4 citation statements)

References 56 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…This could be due to the inconsistency between the enthalpy of formation of UTe and the partial pressure data as already pointed out by Czechowitz [22]. Comparison with the experimental data from Baskin et al [23], the models from Czechowitz [19] and Wolf [20], and the DFT calculations from Qian [25] and the OQMD database [26]. Comparison with the estimated data from Westrum [21] and the model of Wolf [20].…”

Section: Calphad Assessmentmentioning

confidence: 94%

“…More recently, density functional theory (DFT) calculations were performed on U-Te compounds by Qian et al [25]. Additionally, other DFT data are available in the OQMD database [26].…”

Section: Thermodynamic Datamentioning

confidence: 99%

“…Figure 4. Calculated enthalpy of formation of UTe, U 3 Te 4 , U 2 Te 3 , U 3 Te 5 , UTe 2 , U 2 Te 5 , UTe 3 , and UTe 5 .Comparison with the experimental data from Baskin et al[23], the models from Czechowitz[19] and Wolf[20], and the DFT calculations from Qian[25] and the OQMD database[26].…”

mentioning

confidence: 99%

See 2 more Smart Citations

Thermodynamic Modeling of the Uranium–Tellurium System: Estimation of the Uncertainties by a Bayesian Approach

Guéneau

Lawrence

Klein

et al. 2022

Thermo

View full text Add to dashboard Cite

Under irradiation, the formation of fission products in the (U,Pu)O2 fuel with time has a substantial effect on its chemistry. In particular, migration of the most volatile fission products (Cs, Te, I, Mo) from the center to the periphery of the fuel pellet is induced by the large radial thermal gradient. To predict the thermodynamic properties of the irradiated fuel, thermodynamic modeling of the complex multi-component (Cs-I-Te-Mo)–(U-Pu)–O system is performed using the CALPHAD method. In this work, the thermodynamic assessment of the U–Te sub-system is performed. The literature review reveals a lack of experimental data as well as scattering and inconsistency of some of the data. In particular, no thermodynamic data exist on the liquid. From this review, input thermodynamic and phase diagram data are carefully selected. The Gibbs energy functions are then adjusted by fitting these data. An overall good agreement is obtained with all the selected data except for the enthalpy of formation for UTe which is underestimated by 13% by our model. This could be due to an inconsistency between the enthalpy of formation and vapor pressure data. In a second step, the uncertainties on the thermodynamic parameters and their propagation on the calculated thermodynamic and phase diagram data are estimated using a Bayesian approach. The analysis shows that there are too many parameters (22) for too few data points (120 points). The uncertainties are thus large on some of the calculated data. Moreover the inconsistency of some of the data and the lack of thermodynamic data for the liquid makes the model uncertain. New experimental data such as heat capacity, enthalpy of formation for the compounds, and chemical potentials or activities for the liquid phase would improve the reliability of our model. Measurements of phase diagram data in the U–UTe2 region are also required. However this work provides the first detailed uncertainty analysis of the U–Te CALPHAD model. Moreover our approach, contrary to other Bayesian methods, provides an analytical posterior probability distribution and analytical credible intervals for the calculated thermodynamic quantities. It also speeds up the simulation of the uncertainty estimations on the phase diagram.

show abstract

Section: Calphad Assessmentmentioning

confidence: 94%

“…More recently, density functional theory (DFT) calculations were performed on U-Te compounds by Qian et al [25]. Additionally, other DFT data are available in the OQMD database [26].…”

Section: Thermodynamic Datamentioning

confidence: 99%

See 1 more Smart Citation

Thermodynamic Modeling of the Uranium–Tellurium System: Estimation of the Uncertainties by a Bayesian Approach

Guéneau

Lawrence

Klein

et al. 2022

Thermo

View full text Add to dashboard Cite

show abstract

“…In particular, the strongly correlated Hubbard model was employed to describe the 5f electrons of U atoms within the GGA + U method . After a series of tests and comparison with other related studies, , the effective Hubbard U eff ( U eff = U – J , i.e., the difference between Coulomb U and exchange J values) was set to 2 eV.…”

Section: Computational Detailsmentioning

confidence: 99%

Origin of Near-Zero Thermal Expansion in A₂O(PO₄)₂ Oxides over an Ultrawide Temperature Range

Gao

Sanson

et al. 2022

J. Phys. Chem. C

View full text Add to dashboard Cite

The near-zero thermal expansion of A 2 O(PO 4 ) 2 oxides (A = Th, U, Zr, and Hf) is investigated by first-principles calculations, and the role of structural flexibility, strongly related to transverse vibrations, is clarified. The results of lattice dynamics simulations indicate that the low positive or negative thermal expansion of A 2 O(PO 4 ) 2 mainly originates from the competition between phonon modes with positive and negative Gruneisen parameters in the low-frequency range. This work provides new insights to help the discovery and design of new materials with ultralow or controlled thermal expansion.

show abstract

Rare Bird: U⁺⁵ in Uranium Chalcogenides

Berseneva,

Klepov,

Kashem

et al. 2024

Chem. Mater.

View full text Add to dashboard Cite

Chalcogen environments tend to stabilize low oxidation states, thus making the +5 oxidation state in uranium chalcogenides extremely rare. Having one unpaired electron, the magnetism of U+5, 5f1, is of significant interest; however, it is underexplored due to a scarcity of examples. Three related all-U+5 chalcogenides, Na2Cu5US6, Na3Cu4US6, and Na3Cu4USe6, were obtained as single crystals via the flux-assisted boron chalcogen mixture method as part of a broader investigation of the Na–Cu–U–Q (Q = S and Se) systems. To test the formation of the Se-analog of Na2Cu5US6, we performed in situ high-temperature powder X-ray diffraction using sealed capillaries; this approach demonstrated the formation and presence of only Na3Cu4USe6 and not “Na2Cu5USe6” in the reaction mixture. In addition to assigning oxidation states using charge balance and the sample composition, oxidation states of copper, +1, and uranium, +5, in Na2Cu5US6 were also determined via X-ray absorption near edge spectroscopy. Magnetic properties were investigated on both bulk powder samples of Na2Cu5US6 and Na3Cu4UQ 6 (Q = S and Se) and millimeter-size single crystals of Na2Cu5US6, where magnetic susceptibility and magnetization vs field measurements revealed antiferromagnetic behavior of Na2Cu5US6 and Na3Cu4UQ 6 (Q = S and Se) with a T N of 4.7, 3.4, and 5.9 K, respectively. Finally, a broad discussion of the effective magnetic moment of U+5, which is significantly smaller, 1.06 μB in Na2Cu5US6 and 1.08 μB in Na3Cu4USe6, than predicted by spin-only (1.73 μB) and total angular momentum (2.54 μB) models. The fact that only about 20 compositions of such materials are currently known, highlights the need to explore additional compositions containing uranium in rare oxidation states before it will be possible to understand the magnetic properties of such materials more fully.

show abstract

Theoretical Assignment of Oxidation State of Uranium in Binary, Ternary, and Quaternary Tellurides

Cited by 3 publications

References 56 publications

Thermodynamic Modeling of the Uranium–Tellurium System: Estimation of the Uncertainties by a Bayesian Approach

Thermodynamic Modeling of the Uranium–Tellurium System: Estimation of the Uncertainties by a Bayesian Approach

Origin of Near-Zero Thermal Expansion in A₂O(PO₄)₂ Oxides over an Ultrawide Temperature Range

Rare Bird: U⁺⁵ in Uranium Chalcogenides

Contact Info

Product

Resources

About

Theoretical Assignment of Oxidation State of Uranium in Binary, Ternary, and Quaternary Tellurides

Cited by 3 publications

References 56 publications

Thermodynamic Modeling of the Uranium–Tellurium System: Estimation of the Uncertainties by a Bayesian Approach

Thermodynamic Modeling of the Uranium–Tellurium System: Estimation of the Uncertainties by a Bayesian Approach

Origin of Near-Zero Thermal Expansion in A2O(PO4)2 Oxides over an Ultrawide Temperature Range

Rare Bird: U+5 in Uranium Chalcogenides

Contact Info

Product

Resources

About

Origin of Near-Zero Thermal Expansion in A₂O(PO₄)₂ Oxides over an Ultrawide Temperature Range

Rare Bird: U⁺⁵ in Uranium Chalcogenides