Materials Data on Ba2AlCu2F11 by Materials Project
Ba2Cu2AlF11 crystallizes in the trigonal P3_2 space group. The structure is three-dimensional. there are two inequivalent Ba2+ sites. In the first Ba2+ site, Ba2+ is bonded in a 12-coordinate geometry to twelve F1- atoms. There are a spread of Ba–F bond distances ranging from 2.70–3.27 Å. In the second Ba2+ site, Ba2+ is bonded in a 8-coordinate geometry to eight F1- atoms. There are a spread of Ba–F bond distances ranging from 2.70–2.90 Å. There are two inequivalent Cu2+ sites. In the first Cu2+ site, Cu2+ is bonded to six F1- atoms to form distorted CuF6 octahedra that share corners with two equivalent AlF6 octahedra, a cornercorner with one CuF5 square pyramid, and an edgeedge with one CuF5 square pyramid. The corner-sharing octahedra tilt angles range from 51–63°. There are a spread of Cu–F bond distances ranging from 1.91–2.40 Å. In the second Cu2+ site, Cu2+ is bonded to five F1- atoms to form distorted CuF5 square pyramids that share a cornercorner with one CuF6 octahedra, corners with two equivalent AlF6 octahedra, and an edgeedge with one CuF6 octahedra. The corner-sharing octahedra tilt angles range from 53–63°. There are a spread of Cu–F bond distances ranging from 1.91–2.25 Å. Al3+ is bonded to six F1- atoms to form AlF6 octahedra that share corners with two equivalent CuF6 octahedra and corners with two equivalent CuF5 square pyramids. The corner-sharing octahedra tilt angles range from 51–63°. There are a spread of Al–F bond distances ranging from 1.80–1.87 Å. There are eleven inequivalent F1- sites. In the first F1- site, F1- is bonded in a bent 120 degrees geometry to one Ba2+, one Cu2+, and one Al3+ atom. In the second F1- site, F1- is bonded in a distorted single-bond geometry to one Ba2+ and one Al3+ atom. In the third F1- site, F1- is bonded in a distorted water-like geometry to two Ba2+ and two Cu2+ atoms. In the fourth F1- site, F1- is bonded in a 1-coordinate geometry to two Ba2+ and one Cu2+ atom. In the fifth F1- site, F1- is bonded in a distorted single-bond geometry to two Ba2+, one Cu2+, and one Al3+ atom. In the sixth F1- site, F1- is bonded in a distorted single-bond geometry to three Ba2+ and one Cu2+ atom. In the seventh F1- site, F1- is bonded in a distorted single-bond geometry to three Ba2+ and one Al3+ atom. In the eighth F1- site, F1- is bonded in a distorted bent 120 degrees geometry to one Ba2+ and two Cu2+ atoms. In the ninth F1- site, F1- is bonded in a distorted single-bond geometry to two Ba2+ and one Al3+ atom. In the tenth F1- site, F1- is bonded in a distorted single-bond geometry to two Ba2+ and one Cu2+ atom. In the eleventh F1- site, F1- is bonded in a 1-coordinate geometry to one Ba2+, two Cu2+, and one Al3+ atom.