Solid Solutions LnxU1−xC2 with Ln = Tb, Dy, Ho, Tm, and Lu Showing Ideal Vegard Behavior

IF 3.1 4区化学 Q2 CHEMISTRY, INORGANIC & NUCLEAR

Inorganics Pub Date : 2023-11-25 DOI:10.3390/inorganics11120457

Christian Tobeck, Heiko Wende, U. Ruschewitz

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Abstract

The reaction of UO2 with the respective lanthanide metal and purified graphite in an arc-melting furnace led to the formation of solid solutions of the composition LnxU1−xC2, with Ln = Tb, Dy, Ho, Tm, and Lu. They all crystallize in the tetragonal CaC2 type structure (I4/mmm, Z = 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 Le Bail fits of high-resolution synchrotron powder diffraction data (beamline P02.1, DESY, Hamburg, Germany; beamline BL 09, DELTA, Dortmund, Germany), revealing ideal Vegard behavior for all five solid solutions. XANES investigations on all compounds at the Ln-LIII and U-LIII edges reveal that the occupancies of the U-6d orbitals decrease with increasing x, whereas the occupancies of the Ln-5d orbitals increase, pointing to an electron transfer from the uranium to the lanthanide cations. Examination of the shifts of the absorption edge (E0) leads to the same finding.

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Ln = Tb、Dy、Ho、Tm 和 Lu 的固体溶液 LnxU1-xC2 显示理想的 Vegard 行为

在电弧熔炉中，二氧化铀与相应的镧系元素金属和纯石墨发生反应，形成了成分为 LnxU1-xC2 的固溶体，其中 Ln = Tb、Dy、Ho、Tm 和 Lu。它们都以四方 CaC2 型结构（I4/mmm，Z = 2）结晶。对部分样品进行的元素分析（EDX）证实，所得固溶体的成分与起始材料的标称（称重）成分基本一致，即在电弧熔融合成过程中不会出现镧系金属的大量蒸发。通过对高分辨率同步辐射粉末衍射数据进行 Le Bail 拟合（光束线 P02.1，DESY，德国汉堡；光束线 BL 09，DELTA，德国多特蒙德），提取了固溶体的晶格参数，发现所有五种固溶体都具有理想的 Vegard 行为。在 Ln-LIII 和 U-LIII 边缘对所有化合物进行的 XANES 研究表明，随着 x 的增加，U-6d 轨道的占有率降低，而 Ln-5d 轨道的占有率增加，这表明电子从铀转移到了镧系阳离子。对吸收边（E0）移动的研究也得出了同样的结论。

本文章由计算机程序翻译，如有差异，请以英文原文为准。

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来源期刊

Inorganics Chemistry-Inorganic Chemistry

CiteScore

2.80

自引率

10.30%

发文量

193

审稿时长

6 weeks

期刊介绍： Inorganics is an open access journal that covers all aspects of inorganic chemistry research. Topics include but are not limited to: synthesis and characterization of inorganic compounds, complexes and materials structure and bonding in inorganic molecular and solid state compounds spectroscopic, magnetic, physical and chemical properties of inorganic compounds chemical reactivity, physical properties and applications of inorganic compounds and materials mechanisms of inorganic reactions organometallic compounds inorganic cluster chemistry heterogenous and homogeneous catalytic reactions promoted by inorganic compounds thermodynamics and kinetics of significant new and known inorganic compounds supramolecular systems and coordination polymers bio-inorganic chemistry and applications of inorganic compounds in biological systems and medicine environmental and sustainable energy applications of inorganic compounds and materials MD