Materials Data on BaSr11Al4(O4F)4 by Materials Project

Abstract

BaSr11Al4(O4F)4 crystallizes in the tetragonal P422 space group. The structure is three-dimensional. Ba2+ is bonded in a distorted q6 geometry to eight equivalent O2- and two equivalent F1- atoms. All Ba–O bond lengths are 2.93 Å. Both Ba–F bond lengths are 2.87 Å. There are four inequivalent Sr2+ sites. In the first Sr2+ site, Sr2+ is bonded in a 8-coordinate geometry to six O2- and two F1- atoms. There are a spread of Sr–O bond distances ranging from 2.48–2.74 Å. There are one shorter (2.55 Å) and one longer (2.56 Å) Sr–F bond lengths. In the second Sr2+ site, Sr2+ is bonded in a distorted q6 geometry to eight equivalent O2- and two equivalent F1- atoms. All Sr–O bond lengths are 2.89 Å. Both Sr–F bond lengths are 2.82 Å. In the third Sr2+ site, Sr2+ is bonded in a distorted q6 geometry to eight equivalent O2- and two equivalent F1- atoms. All Sr–O bond lengths are 2.87 Å. Both Sr–F bond lengths are 2.83 Å. In the fourth Sr2+ site, Sr2+ is bonded in a 10-coordinate geometry to eight equivalent O2- and two equivalent F1- atoms. All Sr–O bond lengths are 2.89 Å. Both Sr–F bond lengths are 2.77 Å. There are two inequivalent Al3+ sites. In the first Al3+ site, Al3+ is bonded in a tetrahedral geometry to four equivalent O2- atoms. All Al–O bond lengths are 1.80 Å. In the second Al3+ site, Al3+ is bonded in a tetrahedral geometry to four equivalent O2- atoms. All Al–O bond lengths are 1.80 Å. There are two inequivalent O2- sites. In the first O2- site, O2- is bonded in a 6-coordinate geometry to one Ba2+, four Sr2+, and one Al3+ atom. In the second O2- site, O2- is bonded in a 6-coordinate geometry to five Sr2+ and one Al3+ atom. There are two inequivalent F1- sites. In the first F1- site, F1- is bonded to one Ba2+ and five Sr2+ atoms to form corner-sharing FBaSr5 octahedra. The corner-sharing octahedra tilt angles range from 0–36°. In the second F1- site, F1- is bonded to six Sr2+ atoms to form corner-sharing FSr6 octahedra. The corner-sharing octahedra tilt angles range from 0–36°.