DOE OSTI2020
La7Sb11Br4 crystallizes in the orthorhombic Pnma space group. The structure is three-dimensional. there are seven inequivalent La3+ sites. In the first La3+ site, La3+ is bonded in a 2-coordinate geometry to six Sb+1.55- and three Br1- atoms. There are a spread of La–Sb bond distances ranging from 3.37–3.50 Å. There are two shorter (3.03 Å) and one longer (3.50 Å) La–Br bond lengths. In the second La3+ site, La3+ is bonded in a 9-coordinate geometry to nine Sb+1.55- atoms. There are a spread of La–Sb bond distances ranging from 3.31–3.48 Å. In the third La3+ site, La3+ is bonded in a 4-coordinate geometry to four Sb+1.55- and four Br1- atoms. There are a spread of La–Sb bond distances ranging from 3.34–3.41 Å. There are two shorter (3.02 Å) and two longer (3.06 Å) La–Br bond lengths. In the fourth La3+ site, La3+ is bonded in a 9-coordinate geometry to nine Sb+1.55- atoms. There are a spread of La–Sb bond distances ranging from 3.31–3.44 Å. In the fifth La3+ site, La3+ is bonded in a 9-coordinate geometry to six Sb+1.55- and three Br1- atoms. There are a spread of La–Sb bond distances ranging from 3.33–3.44 Å. There are one shorter (3.12 Å) and two longer (3.22 Å) La–Br bond lengths. In the sixth La3+ site, La3+ is bonded in a 9-coordinate geometry to six Sb+1.55- and three Br1- atoms. There are a spread of La–Sb bond distances ranging from 3.35–3.47 Å. There are one shorter (3.10 Å) and two longer (3.22 Å) La–Br bond lengths. In the seventh La3+ site, La3+ is bonded in a 9-coordinate geometry to nine Sb+1.55- atoms. There are a spread of La–Sb bond distances ranging from 3.30–3.44 Å. There are eleven inequivalent Sb+1.55- sites. In the first Sb+1.55- site, Sb+1.55- is bonded in a 7-coordinate geometry to five La3+ and two equivalent Sb+1.55- atoms. Both Sb–Sb bond lengths are 3.14 Å. In the second Sb+1.55- site, Sb+1.55- is bonded in a 8-coordinate geometry to four La3+ and four Sb+1.55- atoms. Both Sb–Sb bond lengths are 3.12 Å. In the third Sb+1.55- site, Sb+1.55- is bonded to six La3+ atoms to form distorted face-sharing SbLa6 pentagonal pyramids. In the fourth Sb+1.55- site, Sb+1.55- is bonded in a 8-coordinate geometry to four La3+ and four Sb+1.55- atoms. There are two shorter (3.04 Å) and two longer (3.21 Å) Sb–Sb bond lengths. In the fifth Sb+1.55- site, Sb+1.55- is bonded in a 8-coordinate geometry to four La3+ and four Sb+1.55- atoms. Both Sb–Sb bond lengths are 3.23 Å. In the sixth Sb+1.55- site, Sb+1.55- is bonded in a 7-coordinate geometry to five La3+ and two equivalent Sb+1.55- atoms. In the seventh Sb+1.55- site, Sb+1.55- is bonded in a 7-coordinate geometry to five La3+ and two equivalent Sb+1.55- atoms. Both Sb–Sb bond lengths are 3.19 Å. In the eighth Sb+1.55- site, Sb+1.55- is bonded in a 8-coordinate geometry to four La3+ and four Sb+1.55- atoms. Both Sb–Sb bond lengths are 3.07 Å. In the ninth Sb+1.55- site, Sb+1.55- is bonded in a 8-coordinate geometry to four La3+ and four Sb+1.55- atoms. In the tenth Sb+1.55- site, Sb+1.55- is bonded in a 8-coordinate geometry to four La3+ and four Sb+1.55- atoms. There are two shorter (3.03 Å) and two longer (3.21 Å) Sb–Sb bond lengths. In the eleventh Sb+1.55- site, Sb+1.55- is bonded in a 8-coordinate geometry to four La3+ and four Sb+1.55- atoms. There are four inequivalent Br1- sites. In the first Br1- site, Br1- is bonded in a trigonal non-coplanar geometry to three La3+ atoms. In the second Br1- site, Br1- is bonded in a distorted rectangular see-saw-like geometry to four La3+ atoms. In the third Br1- site, Br1- is bonded in a 2-coordinate geometry to three La3+ atoms. In the fourth Br1- site, Br1- is bonded in a trigonal non-coplanar geometry to three La3+ atoms.