Materials Data on BaBi2(IO)2 by Materials Project

Abstract

BaBi2(OI)2 crystallizes in the tetragonal I4mm space group. The structure is two-dimensional and consists of two BaBi2(OI)2 sheets oriented in the (0, 0, 1) direction. Ba2+ is bonded to five I1- atoms to form BaI5 square pyramids that share corners with four equivalent BaI5 square pyramids, corners with four equivalent BiIO4 square pyramids, and edges with four equivalent BaI5 square pyramids. There are one shorter (3.12 Å) and four longer (3.47 Å) Ba–I bond lengths. There are two inequivalent Bi2+ sites. In the first Bi2+ site, Bi2+ is bonded to four equivalent O2- and one I1- atom to form distorted BiIO4 square pyramids that share corners with four equivalent BaI5 square pyramids and corners with four equivalent BiIO4 square pyramids. All Bi–O bond lengths are 2.44 Å. The Bi–I bond length is 3.42 Å. In the second Bi2+ site, Bi2+ is bonded in a distorted square co-planar geometry to four equivalent O2- atoms. All Bi–O bond lengths are 2.50 Å. O2- is bonded in a rectangular see-saw-like geometry to four Bi2+ atoms. There are two inequivalent I1- sites. In the first I1- site, I1- is bonded in a single-bond geometry to one Ba2+ atom. In the second I1- site, I1- is bonded to four equivalent Ba2+ and one Bi2+ atom to form a mixture of distorted edge and corner-sharing IBa4Bi square pyramids.