DOE OSTI2020
TbFeSb3 crystallizes in the orthorhombic Pbcm space group. The structure is three-dimensional. there are two inequivalent Tb3+ sites. In the first Tb3+ site, Tb3+ is bonded in a 9-coordinate geometry to nine Sb2- atoms. There are a spread of Tb–Sb bond distances ranging from 3.16–3.37 Å. In the second Tb3+ site, Tb3+ is bonded in a 9-coordinate geometry to nine Sb2- atoms. There are a spread of Tb–Sb bond distances ranging from 3.14–3.29 Å. Fe3+ is bonded to six Sb2- atoms to form a mixture of distorted edge, face, and corner-sharing FeSb6 octahedra. The corner-sharing octahedral tilt angles are 43°. There are a spread of Fe–Sb bond distances ranging from 2.59–2.68 Å. There are five inequivalent Sb2- sites. In the first Sb2- site, Sb2- is bonded in a 6-coordinate geometry to four Tb3+ and two equivalent Fe3+ atoms. In the second Sb2- site, Sb2- is bonded in a 5-coordinate geometry to one Tb3+, four equivalent Fe3+, and one Sb2- atom. The Sb–Sb bond length is 3.08 Å. In the third Sb2- site, Sb2- is bonded in a 5-coordinate geometry to one Tb3+ and four equivalent Fe3+ atoms. In the fourth Sb2- site, Sb2- is bonded in a 7-coordinate geometry to four Tb3+, two equivalent Fe3+, and one Sb2- atom. In the fifth Sb2- site, Sb2- is bonded in a 8-coordinate geometry to four Tb3+ and four equivalent Sb2- atoms. There are a spread of Sb–Sb bond distances ranging from 2.99–3.05 Å.