DOE OSTI2020
Ho(IrSi)2 crystallizes in the tetragonal P4/nmm space group. The structure is three-dimensional. Ho is bonded in a 8-coordinate geometry to eight Ir and eight Si atoms. There are four shorter (3.13 Å) and four longer (3.25 Å) Ho–Ir bond lengths. There are four shorter (3.16 Å) and four longer (3.18 Å) Ho–Si bond lengths. There are two inequivalent Ir sites. In the first Ir site, Ir is bonded to four equivalent Ho and four equivalent Si atoms to form distorted IrHo4Si4 tetrahedra that share corners with twelve equivalent SiHo4Ir4 tetrahedra, edges with two equivalent SiHo4Ir4 tetrahedra, edges with four equivalent IrHo4Si4 tetrahedra, and faces with four equivalent IrHo4Si4 tetrahedra. All Ir–Si bond lengths are 2.43 Å. In the second Ir site, Ir is bonded in a 9-coordinate geometry to four equivalent Ho and five Si atoms. There are one shorter (2.37 Å) and four longer (2.42 Å) Ir–Si bond lengths. There are two inequivalent Si sites. In the first Si site, Si is bonded to four equivalent Ho and four equivalent Ir atoms to form distorted SiHo4Ir4 tetrahedra that share corners with twelve equivalent IrHo4Si4 tetrahedra, edges with two equivalent IrHo4Si4 tetrahedra, edges with four equivalent SiHo4Ir4 tetrahedra, and faces with four equivalent SiHo4Ir4 tetrahedra. In the second Si site, Si is bonded in a 9-coordinate geometry to four equivalent Ho and five Ir atoms.