New quaternary compounds R₂TAl₄Ge₂ (R = Y, Sm, Gd-Lu, T = Fe, Ni)

Chem. Met. Alloys 15 (2022) 17-21

https://doi.org/10.30970/cma15.0424

Svitlana PUKAS, Nataliya SEMUSO, Roman GLADYSHEVSKII

Nine rare-earth iron and nine rare-earth nickel alumogermanides R₂FeAl₄Ge₂ (R = Y, Sm, Gd, Tb, Dy, Ho, Er, Tm, Lu) and R₂NiAl₄Ge₂ (R = Y, Sm, Gd, Tb, Dy, Ho, Er, Tm, Yb) were synthesized by arc melting and their crystal structures were studied by X-ray powder diffraction. They are isotypic to Tb₂NiAl₄Ge₂, Pearson symbol tI18, space group I4/mmm. The tetragonal structure type Tb₂NiAl₄Ge₂ is a quaternary variant of the ternary type Yb₃F₄S₂: Yb₃F₄S₂ ≡ (NiGe₂)Al₄Tb₂. It belongs to a family of structures with cubic coordination of the smallest atoms (Fe or Ni).

Alternation of two types of layer containing cubes along the crystallographic direction [001] in the structure of Y₂FeAl₄Ge₂.

Keywords

Quaternary alumogermanide / X-ray powder diffraction / Crystal structure / Isotypic compounds