Materials Data on SrCaI4 by Materials Project

Abstract

SrCaI4 crystallizes in the monoclinic P2_1/c space group. The structure is three-dimensional. Sr2+ is bonded to seven I1- atoms to form distorted SrI7 pentagonal bipyramids that share corners with four equivalent SrI7 pentagonal bipyramids, an edgeedge with one SrI7 pentagonal bipyramid, and edges with four equivalent CaI5 trigonal bipyramids. There are a spread of Sr–I bond distances ranging from 3.41–3.50 Å. Ca2+ is bonded to five I1- atoms to form CaI5 trigonal bipyramids that share edges with four equivalent SrI7 pentagonal bipyramids and an edgeedge with one CaI5 trigonal bipyramid. There are a spread of Ca–I bond distances ranging from 3.03–3.13 Å. There are four inequivalent I1- sites. In the first I1- site, I1- is bonded in a distorted T-shaped geometry to two equivalent Sr2+ and one Ca2+ atom. In the second I1- site, I1- is bonded in a 3-coordinate geometry to one Sr2+ and two equivalent Ca2+ atoms. In the third I1- site, I1- is bonded in a T-shaped geometry to two equivalent Sr2+ and one Ca2+ atom. In the fourth I1- site, I1- is bonded in a 3-coordinate geometry to two equivalent Sr2+ and one Ca2+ atom.