Materials Data on Ba2Sr7I18 by Materials Project
Ba2Sr7I18 crystallizes in the triclinic P-1 space group. The structure is three-dimensional. Ba2+ is bonded in a 7-coordinate geometry to seven I1- atoms. There are a spread of Ba–I bond distances ranging from 3.49–4.12 Å. There are four inequivalent Sr2+ sites. In the first Sr2+ site, Sr2+ is bonded to six I1- atoms to form a mixture of corner and edge-sharing SrI6 octahedra. The corner-sharing octahedra tilt angles range from 51–65°. There are a spread of Sr–I bond distances ranging from 3.23–3.48 Å. In the second Sr2+ site, Sr2+ is bonded to six I1- atoms to form a mixture of corner and edge-sharing SrI6 octahedra. The corner-sharing octahedra tilt angles range from 62–66°. There are four shorter (3.29 Å) and two longer (3.39 Å) Sr–I bond lengths. In the third Sr2+ site, Sr2+ is bonded to six I1- atoms to form a mixture of corner and edge-sharing SrI6 octahedra. The corner-sharing octahedra tilt angles range from 51–64°. There are a spread of Sr–I bond distances ranging from 3.25–3.44 Å. In the fourth Sr2+ site, Sr2+ is bonded to six I1- atoms to form a mixture of corner and edge-sharing SrI6 octahedra. The corner-sharing octahedra tilt angles range from 53–66°. There are a spread of Sr–I bond distances ranging from 3.22–3.42 Å. There are nine inequivalent I1- sites. In the first I1- site, I1- is bonded in a 2-coordinate geometry to one Ba2+ and two Sr2+ atoms. In the second I1- site, I1- is bonded in a distorted trigonal non-coplanar geometry to one Ba2+ and two Sr2+ atoms. In the third I1- site, I1- is bonded in a distorted trigonal non-coplanar geometry to one Ba2+ and two Sr2+ atoms. In the fourth I1- site, I1- is bonded in a distorted trigonal non-coplanar geometry to three Sr2+ atoms. In the fifth I1- site, I1- is bonded in a 3-coordinate geometry to three Sr2+ atoms. In the sixth I1- site, I1- is bonded in a 3-coordinate geometry to one Ba2+ and two Sr2+ atoms. In the seventh I1- site, I1- is bonded in an L-shaped geometry to two Sr2+ atoms. In the eighth I1- site, I1- is bonded in a 3-coordinate geometry to one Ba2+ and three Sr2+ atoms. In the ninth I1- site, I1- is bonded to two equivalent Ba2+ and two Sr2+ atoms to form a mixture of distorted corner and edge-sharing IBa2Sr2 trigonal pyramids.