DOE OSTI2020
Er5Ni2Bi crystallizes in the tetragonal I4/mcm space group. The structure is three-dimensional. there are two inequivalent Er sites. In the first Er site, Er is bonded to four equivalent Ni and two equivalent Bi atoms to form distorted ErNi4Bi2 octahedra that share corners with six equivalent ErNi4Bi2 octahedra, corners with sixteen equivalent ErNi3Bi2 trigonal bipyramids, and faces with eight equivalent ErNi3Bi2 trigonal bipyramids. The corner-sharing octahedra tilt angles range from 0–52°. All Er–Ni bond lengths are 2.98 Å. Both Er–Bi bond lengths are 3.39 Å. In the second Er site, Er is bonded to three equivalent Ni and two equivalent Bi atoms to form distorted ErNi3Bi2 trigonal bipyramids that share corners with four equivalent ErNi4Bi2 octahedra, corners with twelve equivalent ErNi3Bi2 trigonal bipyramids, edges with seven equivalent ErNi3Bi2 trigonal bipyramids, faces with two equivalent ErNi4Bi2 octahedra, and a faceface with one ErNi3Bi2 trigonal bipyramid. The corner-sharing octahedra tilt angles range from 42–61°. There are two shorter (2.84 Å) and one longer (2.92 Å) Er–Ni bond lengths. Both Er–Bi bond lengths are 3.26 Å. Ni is bonded in a 9-coordinate geometry to eight Er and one Ni atom. The Ni–Ni bond length is 2.76 Å. Bi is bonded in a 10-coordinate geometry to ten Er atoms.