Materials Data on Tm5(SiSb)2 by Materials Project

Abstract

Tm5Sb2Si2 crystallizes in the orthorhombic Cmce space group. The structure is three-dimensional. there are two inequivalent Tm sites. In the first Tm site, Tm is bonded to three equivalent Si and three equivalent Sb atoms to form distorted TmSi3Sb3 pentagonal pyramids that share corners with three equivalent TmSi4Sb2 octahedra, corners with ten equivalent TmSi3Sb3 pentagonal pyramids, edges with seven equivalent TmSi3Sb3 pentagonal pyramids, faces with two equivalent TmSi4Sb2 octahedra, and faces with two equivalent TmSi3Sb3 pentagonal pyramids. The corner-sharing octahedra tilt angles range from 36–41°. There are one shorter (2.89 Å) and two longer (2.98 Å) Tm–Si bond lengths. There are one shorter (3.11 Å) and two longer (3.14 Å) Tm–Sb bond lengths. In the second Tm site, Tm is bonded to four equivalent Si and two equivalent Sb atoms to form TmSi4Sb2 octahedra that share corners with four equivalent TmSi4Sb2 octahedra, corners with twelve equivalent TmSi3Sb3 pentagonal pyramids, and faces with eight equivalent TmSi3Sb3 pentagonal pyramids. The corner-sharing octahedral tilt angles are 50°. There are two shorter (3.02 Å) and two longer (3.03 Å) Tm–Si bond lengths. Both Tm–Sb bond lengths are 3.07 Å. Si is bonded in a 8-coordinate geometry to eight Tm atoms. Sb is bonded to seven Tm atoms to form a mixture of distorted edge and corner-sharing SbTm7 pentagonal bipyramids.