Lu 20 Ir 5 In 3 and Lu 20 Pt 5 In 3 – superstructures of the Al 5 Co 2 type by coloring and distortion

The lutetium‐rich intermetallic compounds Lu 20 Ir 5 In 3 and Lu 20 Pt 5 In 3 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 Lu 20 Ir 5 In 3 and Lu 20 Pt 5 In 3 were refined from single crystal X‐ray diffractometer data: P 2 m , a =1618.53(4), c =919.36(4) pm, wR 2=0.0588, 2665 F 2 values, 88 variables for Lu 20 Ir 5 In 3 and a =1630.58(4), c =920.43(4) pm, wR 2=0.0836, 3024 F 2 values, 89 variables for Lu 19.92 Pt 5 In 3 . The platinum compound showed small amounts of defects on one lutetium site. Lu 20 Ir 5 In 3 and Lu 20 Pt 5 In 3 are non‐centrosymmetric superstructures (through coloring and distortions) that derive from the aristotype Al 5 Co 2 via two steps of symmetry reduction ( P 6 3 / mmc → P 6 3 / mcm → P 2 m ). The structures are discussed together with the coloring variants Y 10 RuCd 3 and Y 9 CoMg 4 on the basis of a group subgroup scheme. Striking features of the Lu 20 Ir 5 In 3 structure are short Ir−Lu contacts and the structural segregation of In 3 triangles (300 and 315 pm In−In) that are solely coordinated by lutetium atoms. Temperature dependent magnetic susceptibility studies of the Lu 20 Ir 5 In 3 and Lu 20 Pt 5 In 3 samples indicate Pauli paramagnetism.