Enthalpies of formation of rare earth orthovanadates, REVO4

Dorogova, M.; Navrotsky, Alexandra; Boatner, L. A.

doi:10.1016/j.jssc.2006.12.001

Cited by 41 publications

(15 citation statements)

References 28 publications

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“…opposite to the rare-earth sesquioxides and niobates. In this respect, it is interesting to note that the trends in formation enthalpy for the pyrochlore 23 and monazite REXO 4 (X = P and V) 24 series of compounds concur; the formation enthalpy increases (less stable oxides) with decreasing RE size, while it is opposite for the rare earth sesquioxides. Furthermore, within the pyrochlore series, the deviation from the ideal pyrochlore structure has been related to the r RE /r X ratio, and the degree of anion and cation disorder increases when the ratio decreases.…”

Section: Hydration Trends Of Binary and Ternary Oxidesmentioning

confidence: 95%

Hydration thermodynamics of pyrochlore structured oxides from TG and first principles calculations

2012

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In this contribution we investigate trends in the defect chemistry and hydration thermodynamics of rare-earth pyrochlore structured oxides, RE(2)X(2)O(7) (RE = La-Lu and X = Ti, Sn, Zr and Ce). First principles density functional theory (DFT) calculations have been performed to elucidate trends in the general defect chemistry and hydration enthalpy for the above-mentioned series. Further, to justify the use of such theoretical methods, the hydration properties of selected compositions were studied by means of thermogravimetric measurements. Both DFT calculations and TG measurements indicate that the hydration enthalpy becomes less exothermic with decreasing radii of RE ions within the RE(2)X(2)O(7) series (X = Ti, Sn, Zr and Ce), while it is less dependent on the X site ion. The observed hydration trends are discussed in connection with trends in the stability of both protons and oxygen vacancies and changes in the electronic density of states and bonding environment through the series. Finally, the findings are discussed with respect to existing correlations for other binary and ternary oxides.

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Section: Hydration Trends Of Binary and Ternary Oxidesmentioning

confidence: 95%

Hydration thermodynamics of pyrochlore structured oxides from TG and first principles calculations

2012

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“…The fluorite structure of stoichiometry AO 2 is adopted by CeO x" coordinate of the 48f "O" site is unconstrained and it can be considered a measure of how "fluorite-like" or "pyrochlore-like" a particular material is, since the transformation between defect fluorite and pyrochlore appears to occur gradually, influenced by temperature and also by radiation damage [30]. Table 3 summarizes enthalpies of formation of RE pyrochlores and Thermodynamic trends in vanadates REVO 4 [33] are similar to those in phosphates REPO 4 . Figure 6 illustrates these trends.…”

Section: Fluorite and Pyrochlorementioning

confidence: 99%

Thermodynamics of solid phases containing rare earth oxides

Navrotsky

Lee

Mielewczyk‐Gryń

et al. 2015

The Journal of Chemical Thermodynamics

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“…High-temperature oxide melt solution calorimetry in which a few milligrams of sample are dissolved in a large volume of molten salt solvent has been applied extensively to oxide systems containing actinides − as well as rare earths (relevant as fission products). − The molten sodium molybdate solvent (3Na 2 O–4MoO 3 ) at 700 or 800 °C works well, however, sometimes molten lead borate (2PbO–B 2 O 3 ) is employed to dissolve specific, often silica-rich, materials. , The standard setup used for the non- and low radioactive materials consists of silica cells containing platinum crucibles holding the melt which are open to air flow. However, such a simple setup is inadequate for handling highly radioactive materials.…”

Section: Experimental Thermochemical Methods For Radioactive Materialsmentioning

confidence: 99%

Thermodynamics of Fluorite-Structured Oxides Relevant to Nuclear Energy: A Review

Shelyug

Navrotsky

2021

ACS Earth Space Chem.

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Fluorite structured materials have shown their applicability in various fields both on and off Earth. In particular, these oxides find extensive application in nuclear energy and the use of actinides in space and planetary settings, thermal and environmental barrier coatings, aerospace applications, catalysts, fuel cells, and batteries. Research done on thermodynamic data collection should be structured to facilitate its use in predictive calculations. In this review, we bring together several decades of experimental thermodynamic analysis of fluorite-based oxides with an emphasis on their relevance to all stages of the nuclear fuel cycle. This review is relatively short in the interest of offering an accessible perspective, especially for scientists early in their careers in nuclear science.

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Enthalpies of formation of rare earth orthovanadates, REVO4

Cited by 41 publications

References 28 publications

Hydration thermodynamics of pyrochlore structured oxides from TG and first principles calculations

Hydration thermodynamics of pyrochlore structured oxides from TG and first principles calculations

Thermodynamics of solid phases containing rare earth oxides

Thermodynamics of Fluorite-Structured Oxides Relevant to Nuclear Energy: A Review

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