Ternary Indides REIrIn (RE = Ce, Sm, Gd–Ho), REIrIn2 (RE = La–Nd, Sm), and Yb2IrIn8

Abstract

AbstractNew ternary indides REIrIn (RE = Ce, Sm, Gd–Ho), REIrIn2 (RE = La–Nd, Sm), and Yb2IrIn8 were synthesized from the elements in sealed tantalum tubes in a high‐frequency furnace. Single crystals were grown through special annealing procedures. Except PrIrIn2, all structures have been refined on the basis of single crystal X‐ray diffractometer data. The equiatomic indides RE IrIn (RE = Ce, Sm, Gd–Ho) crystallize with the hexagonal ZrNiAl type structure, space group $P{\bar 6}{\rm 2}m$. The iridium and indium atoms in REIrIn build up a three‐dimensional network in which the RE atoms fill distorted hexagonal channels. The indium atoms in the indium‐richer intermetallics REIrIn2 (RE = La–Nd, Sm) with orthorhombic MgCuAl2 type structure, space group Cmcm, form a three‐dimensional substructure of distorted corner‐sharing In4/4 tetrahedra. Together, these tetrahedra and the iridium atoms build up a three‐dimensional network in which the RE atoms fill distorted pentagonal channels. Yb2IrIn8 adopts the tetragonal Ho2CoGa8 structure, space group P4/mmm. Geometrical motifs of this structure are layers of YbIn12 cuboctahedra and stuffed IrIn8 cubes. The crystal chemistry and the Ir–In substructures of these intermetallics are discussed.