Materials Data on Sr2CaI6 by Materials Project

Abstract

Sr2CaI6 crystallizes in the monoclinic P2_1/c space group. The structure is three-dimensional. there are two inequivalent Sr2+ sites. In the first Sr2+ site, Sr2+ is bonded to six I1- atoms to form distorted SrI6 octahedra that share corners with five equivalent CaI6 octahedra and an edgeedge with one SrI6 octahedra. The corner-sharing octahedra tilt angles range from 55–62°. There are a spread of Sr–I bond distances ranging from 3.27–3.48 Å. In the second Sr2+ site, Sr2+ is bonded in a 7-coordinate geometry to seven I1- atoms. There are a spread of Sr–I bond distances ranging from 3.21–3.87 Å. Ca2+ is bonded to six I1- atoms to form CaI6 octahedra that share corners with five equivalent SrI6 octahedra and an edgeedge with one CaI6 octahedra. The corner-sharing octahedra tilt angles range from 55–62°. There are a spread of Ca–I bond distances ranging from 3.15–3.30 Å. There are six inequivalent I1- sites. In the first I1- site, I1- is bonded in a distorted trigonal planar geometry to one Sr2+ and two equivalent Ca2+ atoms. In the second I1- site, I1- is bonded in a trigonal non-coplanar geometry to two Sr2+ and one Ca2+ atom. In the third I1- site, I1- is bonded in a 4-coordinate geometry to three Sr2+ and one Ca2+ atom. In the fourth I1- site, I1- is bonded in a distorted trigonal planar geometry to two Sr2+ and one Ca2+ atom. In the fifth I1- site, I1- is bonded in a 2-coordinate geometry to two Sr2+ and one Ca2+ atom. In the sixth I1- site, I1- is bonded in a trigonal non-coplanar geometry to three Sr2+ atoms.