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

New 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 (6) over bar 2m. 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 REIrln(2) (RE = La-Nd, Sm) with orthorbombic MgCuAI(2) type structure, space group Cmcm, form a three-dimensional substructure of distorted corner-sharing In-4/4 tetrahedra. Together, these tetrahedra and the iridium atoms build up a three-dimensional network in which the RE atoms fill distorted pentagonal channels. Yb(2)lrln(8) 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.