Ternary Indides <i>RE</i>₁₀Rh_9±xIn₂₀ (<i>RE</i> = Y, Tb‐Tm, Lu) and YbRhIn₂ ‐ Syntheses and Crystal Chemical Peculiarities

Abstract

Abstract New ternary indides RE 10 Rh 9±x In 20 ( RE = Y, Tb‐Tm, Lu) were synthesized from the elements by arc‐melting under argon and subsequent annealing in alumina or tantalum crucibles. YbRhIn 2 was prepared in a sealed tantalum ampoule in an induction furnace. X‐ray powder and single crystal data for RE 10 Rh 9+x In 20 revealed isotypy with the tetragonal Ho 10 Ni 9 In 20 type structure, space group P 4/ nmm . A crystal of Tm 10 Rh 9 In 20 shows the ideal composition: a = 1335.42(7), c = 921.26(6) pm, wR2 = 0.0524, 1460 F 2 values and 62 variable parameters, while the RE 10 Rh 9 In 20 indides with the lighter rare earth metals contain an additional rhodium site leading to a homogeneity range according to RE 10 Rh 9±x In 20 . This was manifested from X‐ray single crystal data for Y 10 Rh 9.19(1) In 20 , Tb 10 Rh 9.40(1) In 20 , Dy 10 Rh 9.07(1) In 20 , Dy 10 Rh 9.52(1) In 20 , Ho 10 Rh 9.41(1) In 20 , and Er 10 Rh 9.27(1) In 20 . On the other hand, defects were found for the Rh2 site of Lu 10 Rh 8.87(1) In 20 . The crystal chemistry of the RE 10 Rh 9 In 20 indides and the structurally related RE PdIn 2 indides with tetragonal HfNiGa 2 structure is discussed. YbRhIn 2 was synthesized in a sealed tantalum ampoule. It adopts the orthorhombic MgCuAl 2 type structure: Cmcm , a = 418.24(6), b = 1024.0(2), c = 807.5(1) pm, wR2 = 0.0477, 292 F 2 values and 16 variable parameters. The rhodium atoms fill distorted triangles of an orthorhombically distorted YbIn 2 substructure.