Materials Data on Ba3AlAs3 by Materials Project

Abstract

Ba3AlAs3 crystallizes in the orthorhombic Cmce space group. The structure is three-dimensional. there are two inequivalent Ba2+ sites. In the first Ba2+ site, Ba2+ is bonded in a 6-coordinate geometry to six As3- atoms. There are a spread of Ba–As bond distances ranging from 3.32–3.78 Å. In the second Ba2+ site, Ba2+ is bonded to six As3- atoms to form distorted BaAs6 octahedra that share corners with five equivalent BaAs6 octahedra, corners with four equivalent AlAs4 tetrahedra, edges with eight equivalent BaAs6 octahedra, and a faceface with one AlAs4 tetrahedra. The corner-sharing octahedra tilt angles range from 15–28°. There are a spread of Ba–As bond distances ranging from 3.38–3.66 Å. Al3+ is bonded to four As3- atoms to form AlAs4 tetrahedra that share corners with eight equivalent BaAs6 octahedra, an edgeedge with one AlAs4 tetrahedra, and faces with two equivalent BaAs6 octahedra. The corner-sharing octahedra tilt angles range from 35–53°. All Al–As bond lengths are 2.54 Å. There are two inequivalent As3- sites. In the first As3- site, As3- is bonded in a 8-coordinate geometry to six Ba2+ and two equivalent Al3+ atoms. In the second As3- site, As3- is bonded in a 7-coordinate geometry to six Ba2+ and one Al3+ atom.