Materials Data on BaCa2I6 by Materials Project

Abstract

BaCa2I6 is Molybdenite-derived structured and crystallizes in the monoclinic P2_1/c space group. The structure is three-dimensional. Ba2+ is bonded to six I1- atoms to form BaI6 octahedra that share corners with four equivalent CaI6 pentagonal pyramids and edges with four equivalent CaI6 pentagonal pyramids. There are two shorter (3.43 Å) and four longer (3.49 Å) Ba–I bond lengths. Ca2+ is bonded to six I1- atoms to form distorted CaI6 pentagonal pyramids that share corners with two equivalent BaI6 octahedra, corners with two equivalent CaI6 pentagonal pyramids, edges with two equivalent BaI6 octahedra, and edges with two equivalent CaI6 pentagonal pyramids. The corner-sharing octahedra tilt angles range from 46–75°. There are a spread of Ca–I bond distances ranging from 3.17–3.41 Å. There are three inequivalent I1- sites. In the first I1- site, I1- is bonded in a distorted T-shaped geometry to one Ba2+ and two equivalent Ca2+ atoms. In the second I1- site, I1- is bonded in a 3-coordinate geometry to one Ba2+ and two equivalent Ca2+ atoms. In the third I1- site, I1- is bonded in a distorted T-shaped geometry to one Ba2+ and two equivalent Ca2+ atoms.