Materials Data on Ba2CaI6 by Materials Project

Abstract

Ba2CaI6 crystallizes in the monoclinic P2_1/c space group. The structure is three-dimensional. there are two inequivalent Ba2+ sites. In the first Ba2+ site, Ba2+ is bonded to seven I1- atoms to form distorted BaI7 pentagonal bipyramids that share corners with four equivalent CaI6 octahedra, an edgeedge with one CaI6 octahedra, and edges with two equivalent BaI7 pentagonal bipyramids. The corner-sharing octahedra tilt angles range from 54–64°. There are a spread of Ba–I bond distances ranging from 3.42–3.75 Å. In the second Ba2+ site, Ba2+ is bonded in a 8-coordinate geometry to eight I1- atoms. There are a spread of Ba–I bond distances ranging from 3.37–4.13 Å. Ca2+ is bonded to six I1- atoms to form CaI6 octahedra that share corners with four equivalent BaI7 pentagonal bipyramids, an edgeedge with one CaI6 octahedra, and an edgeedge with one BaI7 pentagonal bipyramid. There are a spread of Ca–I bond distances ranging from 3.07–3.31 Å. There are six inequivalent I1- sites. In the first I1- site, I1- is bonded in a distorted trigonal non-coplanar geometry to one Ba2+ and two equivalent Ca2+ atoms. In the second I1- site, I1- is bonded to three Ba2+ and one Ca2+ atom to form a mixture of distorted edge and corner-sharing IBa3Ca tetrahedra. In the third I1- site, I1- is bonded in a 4-coordinate geometry to three Ba2+ and one Ca2+ atom. In the fourth I1- site, I1- is bonded to three Ba2+ and one Ca2+ atom to form a mixture of distorted edge and corner-sharing IBa3Ca tetrahedra. In the fifth I1- site, I1- is bonded in a 2-coordinate geometry to two Ba2+ and one Ca2+ atom. In the sixth I1- site, I1- is bonded in a distorted trigonal non-coplanar geometry to three Ba2+ atoms.