DOE OSTI2020
Tm5Ni2Bi crystallizes in the tetragonal I4/mcm space group. The structure is three-dimensional. there are two inequivalent Tm sites. In the first Tm site, Tm is bonded to four equivalent Ni and two equivalent Bi atoms to form distorted TmNi4Bi2 octahedra that share corners with six equivalent TmNi4Bi2 octahedra, corners with sixteen equivalent TmNi3Bi2 square pyramids, and faces with eight equivalent TmNi3Bi2 square pyramids. The corner-sharing octahedra tilt angles range from 0–51°. All Tm–Ni bond lengths are 2.94 Å. Both Tm–Bi bond lengths are 3.41 Å. In the second Tm site, Tm is bonded to three equivalent Ni and two equivalent Bi atoms to form distorted TmNi3Bi2 square pyramids that share corners with four equivalent TmNi4Bi2 octahedra, corners with twelve equivalent TmNi3Bi2 square pyramids, edges with seven equivalent TmNi3Bi2 square pyramids, faces with two equivalent TmNi4Bi2 octahedra, and a faceface with one TmNi3Bi2 square pyramid. The corner-sharing octahedra tilt angles range from 42–61°. There are two shorter (2.83 Å) and one longer (2.90 Å) Tm–Ni bond lengths. Both Tm–Bi bond lengths are 3.25 Å. Ni is bonded in a 9-coordinate geometry to eight Tm atoms. Bi is bonded in a 10-coordinate geometry to ten Tm atoms.