DOE OSTI2020
Tb5Bi3 crystallizes in the orthorhombic Pnma space group. The structure is three-dimensional. there are four inequivalent Tb sites. In the first Tb site, Tb is bonded to five Bi atoms to form distorted TbBi5 trigonal bipyramids that share corners with six equivalent TbBi6 octahedra, corners with four equivalent TbBi5 square pyramids, edges with two equivalent TbBi6 octahedra, an edgeedge with one TbBi5 square pyramid, edges with two equivalent TbBi5 trigonal bipyramids, and a faceface with one TbBi5 square pyramid. The corner-sharing octahedra tilt angles range from 30–41°. There are a spread of Tb–Bi bond distances ranging from 3.15–3.39 Å. In the second Tb site, Tb is bonded in a 5-coordinate geometry to five Bi atoms. There are a spread of Tb–Bi bond distances ranging from 3.12–3.52 Å. In the third Tb site, Tb is bonded to five Bi atoms to form distorted TbBi5 square pyramids that share corners with five equivalent TbBi6 octahedra, corners with four equivalent TbBi5 trigonal bipyramids, an edgeedge with one TbBi6 octahedra, edges with two equivalent TbBi5 square pyramids, an edgeedge with one TbBi5 trigonal bipyramid, a faceface with one TbBi6 octahedra, and a faceface with one TbBi5 trigonal bipyramid. The corner-sharing octahedra tilt angles range from 36–46°. There are a spread of Tb–Bi bond distances ranging from 3.21–3.28 Å. In the fourth Tb site, Tb is bonded to six Bi atoms to form distorted TbBi6 octahedra that share corners with five equivalent TbBi5 square pyramids, corners with six equivalent TbBi5 trigonal bipyramids, an edgeedge with one TbBi5 square pyramid, edges with two equivalent TbBi5 trigonal bipyramids, faces with two equivalent TbBi6 octahedra, and a faceface with one TbBi5 square pyramid. There are a spread of Tb–Bi bond distances ranging from 3.15–3.46 Å. There are two inequivalent Bi sites. In the first Bi site, Bi is bonded in a 8-coordinate geometry to eight Tb atoms. In the second Bi site, Bi is bonded in a 9-coordinate geometry to nine Tb atoms.