Single crystal investigation of the YbAl2 compound
| Autor: | Bohdana Belan, Mykola Manyako, Roman Gladyshevskii, Dorota Kowalska |
|---|---|
| Rok vydání: | 2019 |
| Předmět: |
Ytterbium
Valence (chemistry) Scanning electron microscope Analytical chemistry chemistry.chemical_element Crystal structure 010402 general chemistry 010403 inorganic & nuclear chemistry 01 natural sciences 0104 chemical sciences Pearson symbol symbols.namesake chemistry symbols Van der Waals radius Single crystal Diffractometer |
| Zdroj: | Ukrainian Chemistry Journal. 85:25-30 |
| ISSN: | 0041-6045 |
| DOI: | 10.33609/0041-6045.85.9.2019.25-30 |
| Popis: | A sample of nominal composition Yb33,3Al66,7 was synthesized from high-purity elements (Yb ≥ 98.9 wt.% and Al ≥ 99.999 wt.%) by arc-melting under a purified argon atmosphere, using Ti as a getter and a tungsten electrode. To achieve high efficiency of the interaction between the components, the sample was melted twice. The ingot was annealed at 500°C in an evacuated quartz ampoule for 720 h and subsequently quenched in cold water. The weight loss during the preparation of the sample was less than 1 % of the total mass, which was 2 g. The chemical composition of the selected crystals was checked with a field-emission scanning electron microscope (FEINovaNanoSEM 230) equipped with an EDS analyzer. Laue and rotation diffraction patterns of selected single crystals showed cubic symmetry. Integrated intensities measured with graphite-monochromatized Мо Kα radiation (l = 0.71073 Å) on an Xcalibur Atlas CCD diffractometer confirmed the cubic lattice. The structure type MgCu2 was assigned and the structure was refined using the program SHELXL (full-matrix least-squares refinement on F2)] with anisotropic displacement parameters for all of the atoms: Pearson symbol cF24, space group Fd-3m, a = 7.7011(4) Å, V = 456.73(7) Å3, Z = 8, R = 0.0261, Rw = 0.0726 for 42 reflections. It is well-known that the trivalent state is usual one for the rare earth metals. The dependence of the mean atomic volume of the RAl2 binary showed of the so-called “valence” fluctuation state for Eu and Yb. |
| Databáze: | OpenAIRE |
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