Lu20Ir5In3 and Lu20Pt5In3 – superstructures of the Al5Co2 type by coloring and distortion

The lutetium‐rich intermetallic compounds Lu20Ir5In3 and Lu20Pt5In3 were synthesized from the elements in sealed tantalum ampules in an induction furnace. The phase purity of the samples was checked by powder X‐ray diffraction. The structures of Lu20Ir5In3 and Lu20Pt5In3 were refined from single crystal X‐ray diffractometer data: P6‾ 2m, a=1618.53(4), c=919.36(4) pm, wR2=0.0588, 2665 F2 values, 88 variables for Lu20Ir5In3 and a=1630.58(4), c=920.43(4) pm, wR2=0.0836, 3024 F2 values, 89 variables for Lu19.92Pt5In3. The platinum compound showed small amounts of defects on one lutetium site. Lu20Ir5In3 and Lu20Pt5In3 are non‐centrosymmetric superstructures (through coloring and distortions) that derive from the aristotype Al5Co2 via two steps of symmetry reduction (P63/mmc→P63/mcm→P6‾ 2m). The structures are discussed together with the coloring variants Y10RuCd3 and Y9CoMg4 on the basis of a group subgroup scheme. Striking features of the Lu20Ir5In3 structure are short Ir−Lu contacts and the structural segregation of In3 triangles (300 and 315 pm In−In) that are solely coordinated by lutetium atoms. Temperature dependent magnetic susceptibility studies of the Lu20Ir5In3 and Lu20Pt5In3 samples indicate Pauli paramagnetism.