Local Structure in U(IV) and U(V) Environments The Case of U3O7

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Local Structure in U(IV) and U(V) Environments The Case of U3O7. / Leinders, Gregory; Bes, Rene; Kvashnina, Kristina; Verwerft, Marc.

In: Inorganic Chemistry, Vol. 59, No. 7, 11.03.2020, p. 4579-4587.

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Leinders, Gregory ; Bes, Rene ; Kvashnina, Kristina ; Verwerft, Marc. / Local Structure in U(IV) and U(V) Environments The Case of U3O7. In: Inorganic Chemistry. 2020 ; Vol. 59, No. 7. pp. 4579-4587.

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@article{d9d61855bc1545d792e53d3fee59e9cc,
title = "Local Structure in U(IV) and U(V) Environments The Case of U3O7",
abstract = "A comprehensive analysis of X-ray absorption data obtained at the U L3-edge for a systematic series of single-valence (UO2, KUO3, UO3) and mixedvalence uranium compounds (U4O9, U3O7, U3O8) is reported. High-energy resolution fluorescence detection (HERFD) X-ray absorption near-edge spectroscopy (XANES) and extended X-ray absorption fine structure (EXAFS) methods were applied to evaluate U(IV) and U(V) environments, and in particular, to investigate the U3O7 local structure. We find that the valence state distribution in mixed-valence uranium compounds cannot be confidently quantified from a principal component analysis of the U L3-edge XANES data. The spectral line broadening, even when applying the HERFD-XANES method, is sensibly higher (∼3.9 eV) than the observed chemical shifts (∼2.4 eV). Additionally, the white line shape and position are affected not only by the chemical state, but also by crystal field effects, which appear well-resolved in KUO3. The EXAFS of a phase-pure U3O7 sample was assessed based on an average representation of the expanded U60O140 structure. Interatomic U−O distances are found mainly to occur at 2.18 (2), 2.33 (1), and 3.33 (5) {\AA}, and can be seen to correspond to the spatial arrangement of cuboctahedral oxygen clusters. The interatomic distances derived from the EXAFS investigation support a mixed U(IV)−U(V) valence character in U3O7.",
keywords = "Uranium valence state, U3O7, Local structure, XANES, EXAFS",
author = "Gregory Leinders and Rene Bes and Kristina Kvashnina and Marc Verwerft",
note = "Score=10",
year = "2020",
month = "3",
day = "11",
doi = "10.1021/acs.inorgchem.9b03702",
language = "English",
volume = "59",
pages = "4579--4587",
journal = "Inorganic Chemistry",
issn = "0020-1669",
publisher = "ACS - American Chemical Society",
number = "7",

}

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TY - JOUR

T1 - Local Structure in U(IV) and U(V) Environments The Case of U3O7

AU - Leinders, Gregory

AU - Bes, Rene

AU - Kvashnina, Kristina

AU - Verwerft, Marc

N1 - Score=10

PY - 2020/3/11

Y1 - 2020/3/11

N2 - A comprehensive analysis of X-ray absorption data obtained at the U L3-edge for a systematic series of single-valence (UO2, KUO3, UO3) and mixedvalence uranium compounds (U4O9, U3O7, U3O8) is reported. High-energy resolution fluorescence detection (HERFD) X-ray absorption near-edge spectroscopy (XANES) and extended X-ray absorption fine structure (EXAFS) methods were applied to evaluate U(IV) and U(V) environments, and in particular, to investigate the U3O7 local structure. We find that the valence state distribution in mixed-valence uranium compounds cannot be confidently quantified from a principal component analysis of the U L3-edge XANES data. The spectral line broadening, even when applying the HERFD-XANES method, is sensibly higher (∼3.9 eV) than the observed chemical shifts (∼2.4 eV). Additionally, the white line shape and position are affected not only by the chemical state, but also by crystal field effects, which appear well-resolved in KUO3. The EXAFS of a phase-pure U3O7 sample was assessed based on an average representation of the expanded U60O140 structure. Interatomic U−O distances are found mainly to occur at 2.18 (2), 2.33 (1), and 3.33 (5) Å, and can be seen to correspond to the spatial arrangement of cuboctahedral oxygen clusters. The interatomic distances derived from the EXAFS investigation support a mixed U(IV)−U(V) valence character in U3O7.

AB - A comprehensive analysis of X-ray absorption data obtained at the U L3-edge for a systematic series of single-valence (UO2, KUO3, UO3) and mixedvalence uranium compounds (U4O9, U3O7, U3O8) is reported. High-energy resolution fluorescence detection (HERFD) X-ray absorption near-edge spectroscopy (XANES) and extended X-ray absorption fine structure (EXAFS) methods were applied to evaluate U(IV) and U(V) environments, and in particular, to investigate the U3O7 local structure. We find that the valence state distribution in mixed-valence uranium compounds cannot be confidently quantified from a principal component analysis of the U L3-edge XANES data. The spectral line broadening, even when applying the HERFD-XANES method, is sensibly higher (∼3.9 eV) than the observed chemical shifts (∼2.4 eV). Additionally, the white line shape and position are affected not only by the chemical state, but also by crystal field effects, which appear well-resolved in KUO3. The EXAFS of a phase-pure U3O7 sample was assessed based on an average representation of the expanded U60O140 structure. Interatomic U−O distances are found mainly to occur at 2.18 (2), 2.33 (1), and 3.33 (5) Å, and can be seen to correspond to the spatial arrangement of cuboctahedral oxygen clusters. The interatomic distances derived from the EXAFS investigation support a mixed U(IV)−U(V) valence character in U3O7.

KW - Uranium valence state

KW - U3O7

KW - Local structure

KW - XANES

KW - EXAFS

UR - https://ecm.sckcen.be/OTCS/llisapi.dll/open/38907210

U2 - 10.1021/acs.inorgchem.9b03702

DO - 10.1021/acs.inorgchem.9b03702

M3 - Article

VL - 59

SP - 4579

EP - 4587

JO - Inorganic Chemistry

JF - Inorganic Chemistry

SN - 0020-1669

IS - 7

ER -

ID: 6826638