Synthesis, crystal structure and physical properties of Yb11Bi10 −xSnx

Abstract

The intermetallic phase Yb11Bi10 −xSnx (x = 0 and 4.8) crystallizing in the Ho11Ge10 structure type was synthesized and characterized. The crystal structure was established by single-crystal X-ray diffraction data in the tetragonal space group I4/mmm (no.139), Pearson code tI84, Z = 4, a = 12.2043(4) Å, c = 17.7227(9) Å, and V = 2639.7(2) Å3, Rgt(F) = 0.040, 763 observed reflections for Yb11Bi10, and a = 12.0183(5) Å, c = 17.413(1) Å, and V = 2515.1(2) Å3, Rgt(F) = 0.027, 762 observed reflections for Yb11Bi5.2Sn4.8. The crystal structure of Yb11Bi10 contains three discrete anionic moieties: isolated Bi3− anions, Bi24− dimers and Bi44− squares. In Yb11Bi5.2Sn4.8, the square units are formed solely by Sn, and the structure shows a mixed Bi/Sn occupancy at the 8i and 16m Wyckoff sites. Magnetization measurements show that the title phase contains ytterbium exclusively in the 4f14 configuration up to 400 K. The Yb-LIII X-ray absorption spectrum attests also the presence of Yb with a 4f14 (Yb2+) configuration for Yb11Bi10, while the average valence of ytterbium was found to be 2.09 for Yb11Bi5.2Sn4.8.