DOE OSTI2020
Tb3Cu20Sb11 crystallizes in the cubic F-43m space group. The structure is three-dimensional. Tb3+ is bonded in a 8-coordinate geometry to eight Sb3- atoms. There are a spread of Tb–Sb bond distances ranging from 3.18–3.38 Å. There are four inequivalent Cu+1.20+ sites. In the first Cu+1.20+ site, Cu+1.20+ is bonded to four Sb3- atoms to form a mixture of edge and corner-sharing CuSb4 tetrahedra. There are a spread of Cu–Sb bond distances ranging from 2.64–2.77 Å. In the second Cu+1.20+ site, Cu+1.20+ is bonded in a 6-coordinate geometry to three equivalent Cu+1.20+ and three equivalent Sb3- atoms. All Cu–Cu bond lengths are 2.46 Å. All Cu–Sb bond lengths are 2.66 Å. In the third Cu+1.20+ site, Cu+1.20+ is bonded to four Sb3- atoms to form a mixture of edge and corner-sharing CuSb4 tetrahedra. There are a spread of Cu–Sb bond distances ranging from 2.68–2.78 Å. In the fourth Cu+1.20+ site, Cu+1.20+ is bonded to four Sb3- atoms to form a mixture of edge and corner-sharing CuSb4 tetrahedra. There are a spread of Cu–Sb bond distances ranging from 2.68–2.76 Å. There are five inequivalent Sb3- sites. In the first Sb3- site, Sb3- is bonded in a distorted q6 geometry to three equivalent Tb3+ and six Cu+1.20+ atoms. In the second Sb3- site, Sb3- is bonded in a cuboctahedral geometry to twelve equivalent Cu+1.20+ atoms. In the third Sb3- site, Sb3- is bonded in a distorted q6 geometry to three equivalent Tb3+ and six Cu+1.20+ atoms. In the fourth Sb3- site, Sb3- is bonded in a cuboctahedral geometry to twelve equivalent Cu+1.20+ atoms. In the fifth Sb3- site, Sb3- is bonded in a 9-coordinate geometry to two equivalent Tb3+ and seven Cu+1.20+ atoms.