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DOE OSTI · 1296844

Materials Data on Ba2CaI6 by Materials Project

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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 a cornercorner with one CaI6 octahedra, corners with three BaI7 pentagonal bipyramids, edges with two equivalent CaI6 octahedra, and edges with five BaI7 pentagonal bipyramids. The corner-sharing octahedral tilt angles are 63°. There are a spread of Ba–I bond distances ranging from 3.48–3.75 Å. In the second Ba2+ site, Ba2+ is bonded to seven I1- atoms to form distorted BaI7 pentagonal bipyramids that share corners with five equivalent CaI6 octahedra, a cornercorner with one BaI7 pentagonal bipyramid, an edgeedge with one CaI6 octahedra, and edges with four BaI7 pentagonal bipyramids. The corner-sharing octahedra tilt angles range from 35–60°. There are a spread of Ba–I bond distances ranging from 3.49–3.70 Å. Ca2+ is bonded to six I1- atoms to form CaI6 octahedra that share corners with six BaI7 pentagonal bipyramids, an edgeedge with one CaI6 octahedra, and edges with three BaI7 pentagonal bipyramids. There are a spread of Ca–I bond distances ranging from 3.12–3.30 Å. There are six inequivalent I1- sites. In the first I1- site, I1- is bonded to three Ba2+ and one Ca2+ atom to form a mixture of corner and edge-sharing IBa3Ca tetrahedra. In the second I1- site, I1- is bonded to three Ba2+ and one Ca2+ atom to form a mixture of distorted corner and edge-sharing IBa3Ca tetrahedra. In the third I1- site, I1- is bonded in a 3-coordinate geometry to one Ba2+ and two equivalent Ca2+ atoms. In the fourth I1- site, I1- is bonded in a distorted trigonal planar geometry to two equivalent Ba2+ and one Ca2+ atom. In the fifth I1- site, I1- is bonded in a distorted trigonal non-coplanar 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.

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36 MATERIALS SCIENCEBa-Ca-IBa2CaI6crystal structure

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2020-04-29. Materials Data on Ba2CaI6 by Materials Project. https://doi.org/10.17188/1296844

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36 MATERIALS SCIENCE↗