Solid Solutions Ln<sub>x</sub>U<sub>1−x</sub>C<sub>2</sub> with Ln = Tb, Dy, Ho, Tm, and Lu Showing Ideal <i>Vegard</i> Behavior
The reaction of UO<sub>2</sub> with the respective lanthanide metal and purified graphite in an arc-melting furnace led to the formation of solid solutions of the composition Ln<sub>x</sub>U<sub>1−x</sub>C<sub>2</sub>, with Ln = Tb, Dy, Ho, Tm, and Lu....
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| Format: | Article |
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MDPI AG
2023-11-01
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| Series: | Inorganics |
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| Online Access: | https://www.mdpi.com/2304-6740/11/12/457 |
| _version_ | 1797380652000083968 |
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| author | Christian Tobeck Heiko Wende Uwe Ruschewitz |
| author_facet | Christian Tobeck Heiko Wende Uwe Ruschewitz |
| author_sort | Christian Tobeck |
| collection | DOAJ |
| description | The reaction of UO<sub>2</sub> with the respective lanthanide metal and purified graphite in an arc-melting furnace led to the formation of solid solutions of the composition Ln<sub>x</sub>U<sub>1−x</sub>C<sub>2</sub>, with Ln = Tb, Dy, Ho, Tm, and Lu. They all crystallize in the tetragonal CaC<sub>2</sub> type structure (<i>I</i>4/<i>mmm</i>, <i>Z</i> = 2). Elemental analyses of selected samples (EDX) confirm that the composition of the resulting solid solution is in reasonable agreement with the nominal (weighed-in) composition of the starting materials, i.e., a significant evaporation of the lanthanide metals during the arc-melting synthesis does not occur. The lattice parameters of the solid solutions were extracted using <i>Le Bail</i> fits of high-resolution synchrotron powder diffraction data (beamline P02.1, DESY, Hamburg, Germany; beamline BL 09, DELTA, Dortmund, Germany), revealing ideal <i>Vegard</i> behavior for all five solid solutions. XANES investigations on all compounds at the Ln-<i>L<sub>III</sub></i> and U-<i>L<sub>III</sub></i> edges reveal that the occupancies of the U-6<i>d</i> orbitals decrease with increasing <i>x</i>, whereas the occupancies of the Ln-5<i>d</i> orbitals increase, pointing to an electron transfer from the uranium to the lanthanide cations. Examination of the shifts of the absorption edge (<i>E</i><sub>0</sub>) leads to the same finding. |
| first_indexed | 2024-03-08T20:40:19Z |
| format | Article |
| id | doaj.art-eae366a1243040d7a1e2a1091f40ebdd |
| institution | Directory Open Access Journal |
| issn | 2304-6740 |
| language | English |
| last_indexed | 2024-03-08T20:40:19Z |
| publishDate | 2023-11-01 |
| publisher | MDPI AG |
| record_format | Article |
| series | Inorganics |
| spelling | doaj.art-eae366a1243040d7a1e2a1091f40ebdd2023-12-22T14:16:03ZengMDPI AGInorganics2304-67402023-11-01111245710.3390/inorganics11120457Solid Solutions Ln<sub>x</sub>U<sub>1−x</sub>C<sub>2</sub> with Ln = Tb, Dy, Ho, Tm, and Lu Showing Ideal <i>Vegard</i> BehaviorChristian Tobeck0Heiko Wende1Uwe Ruschewitz2Institut für Anorganische Chemie im Department für Chemie, Universität zu Köln, Greinstraße 6, 50939 Köln, GermanyFakultät für Physik and Center for Nanointegration Duisburg-Essen (CENIDE), Universität Duisburg-Essen, Lotharstraße 1, 47057 Duisburg, GermanyInstitut für Anorganische Chemie im Department für Chemie, Universität zu Köln, Greinstraße 6, 50939 Köln, GermanyThe reaction of UO<sub>2</sub> with the respective lanthanide metal and purified graphite in an arc-melting furnace led to the formation of solid solutions of the composition Ln<sub>x</sub>U<sub>1−x</sub>C<sub>2</sub>, with Ln = Tb, Dy, Ho, Tm, and Lu. They all crystallize in the tetragonal CaC<sub>2</sub> type structure (<i>I</i>4/<i>mmm</i>, <i>Z</i> = 2). Elemental analyses of selected samples (EDX) confirm that the composition of the resulting solid solution is in reasonable agreement with the nominal (weighed-in) composition of the starting materials, i.e., a significant evaporation of the lanthanide metals during the arc-melting synthesis does not occur. The lattice parameters of the solid solutions were extracted using <i>Le Bail</i> fits of high-resolution synchrotron powder diffraction data (beamline P02.1, DESY, Hamburg, Germany; beamline BL 09, DELTA, Dortmund, Germany), revealing ideal <i>Vegard</i> behavior for all five solid solutions. XANES investigations on all compounds at the Ln-<i>L<sub>III</sub></i> and U-<i>L<sub>III</sub></i> edges reveal that the occupancies of the U-6<i>d</i> orbitals decrease with increasing <i>x</i>, whereas the occupancies of the Ln-5<i>d</i> orbitals increase, pointing to an electron transfer from the uranium to the lanthanide cations. Examination of the shifts of the absorption edge (<i>E</i><sub>0</sub>) leads to the same finding.https://www.mdpi.com/2304-6740/11/12/457carbideslanthanidessolid solutionsynchrotron powder diffractionuraniumXANES |
| spellingShingle | Christian Tobeck Heiko Wende Uwe Ruschewitz Solid Solutions Ln<sub>x</sub>U<sub>1−x</sub>C<sub>2</sub> with Ln = Tb, Dy, Ho, Tm, and Lu Showing Ideal <i>Vegard</i> Behavior Inorganics carbides lanthanides solid solution synchrotron powder diffraction uranium XANES |
| title | Solid Solutions Ln<sub>x</sub>U<sub>1−x</sub>C<sub>2</sub> with Ln = Tb, Dy, Ho, Tm, and Lu Showing Ideal <i>Vegard</i> Behavior |
| title_full | Solid Solutions Ln<sub>x</sub>U<sub>1−x</sub>C<sub>2</sub> with Ln = Tb, Dy, Ho, Tm, and Lu Showing Ideal <i>Vegard</i> Behavior |
| title_fullStr | Solid Solutions Ln<sub>x</sub>U<sub>1−x</sub>C<sub>2</sub> with Ln = Tb, Dy, Ho, Tm, and Lu Showing Ideal <i>Vegard</i> Behavior |
| title_full_unstemmed | Solid Solutions Ln<sub>x</sub>U<sub>1−x</sub>C<sub>2</sub> with Ln = Tb, Dy, Ho, Tm, and Lu Showing Ideal <i>Vegard</i> Behavior |
| title_short | Solid Solutions Ln<sub>x</sub>U<sub>1−x</sub>C<sub>2</sub> with Ln = Tb, Dy, Ho, Tm, and Lu Showing Ideal <i>Vegard</i> Behavior |
| title_sort | solid solutions ln sub x sub u sub 1 x sub c sub 2 sub with ln tb dy ho tm and lu showing ideal i vegard i behavior |
| topic | carbides lanthanides solid solution synchrotron powder diffraction uranium XANES |
| url | https://www.mdpi.com/2304-6740/11/12/457 |
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