The first quaternary intermetallide with Sc₃Ce₂Si₄-type structure

Chem. Met. Alloys 15 (2022) 8-11

https://doi.org/10.30970/cma15.0422

Svitlana PUKAS, Roksolana KOZAK

The crystal structure of Tm₂Ta₃Ge_2.67Si_1.33 was solved and refined from X-ray single-crystal diffraction data. It is isotypic to Sc₃Ce₂Si₄: Pearson symbol oP36, space group Pnma, a = 6.848(2), b = 13.299(5), c = 7.032(3) Å, Z = 4; R = 0.0329, wR = 0.0817 (for 608 independent reflections with F > 2σ(F) and 50 variables). The structure of the new quaternary compound is partly disordered and characterized by statistic distribution of the smaller atoms, Ge and Si, which form pairs with the shortest distances 2.677(3) and 2.561(4) Å. The structure of Tm₂Ta₃Ge_2.67Si_1.33 can be described as a stacking of slabs along the crystallographic direction [010]. The slabs are formed by Ta-centered rhombic dodecahedra and are connected via common faces.

Projection of the structure of Tm₂Ta₃Ge_2.67Si_1.33 along [100].

Keywords

Germanium / Silicon / Tantalum / Thulium / X-ray single crystal diffraction / Crystal structure