New compounds with Sc₂Re₃Si₄-type structure in the systems R–{Zr,Hf}–Ge

Chem. Met. Alloys 8 (2015) 98-105

https://doi.org/10.30970/cma8.0328

Maryna BOYKO, Nataliya MUTS, Yaroslav TOKAYCHUK, Roman GLADYSHEVSKII

Fifteen Sc₂Re₃Si₄-type (Pearson symbol tP36, space group P4₁2₁2) compounds, Y₂{Zr,Hf}₃Ge₄, Gd₂{Zr,Hf}₃Ge₄, Tb₂{Zr,Hf}₃Ge₄, Dy₂{Zr,Hf}₃Ge₄, Ho₂Hf₃Ge₄, Er₂{Zr,Hf}₃Ge₄, Tm₂{Zr,Hf}₃Ge₄, and Lu₂{Zr,Hf}₃Ge₄, were synthesized and characterized by means of X-ray diffraction and energy-dispersive analyses. The crystal structures of two alloys in the Tm-Zr-Ge and Ho-Hf-Ge systems (Tm_0.88(4)Zr_4.12(4)Ge₄, a = 7.3457(5), c = 13.388(1) Å; Ho_1.38(8)Hf_3.62(8)Ge₄, a = 7.3139(6), c = 13.3550(13) Å) were refined by the Rietveld method on X-ray powder diffraction data. In both structures one of the atom sites was found to be occupied by a statistical mixture of rare-earth metal and Zr (Hf) atoms.

Projection of the unit cell of the structure of Tm_0.88(4)Zr_4.12(4)Ge₄ onto the bc plane and coordination polyhedra of the atoms

Keywords

Rare-earth metals / Zirconium / Hafnium / Germanium / X-ray powder diffraction / Crystal structure