Materials Data on Ba4TiAs4 by Materials Project

Abstract

Ba4TiAs4 crystallizes in the cubic P-43n space group. The structure is three-dimensional. there are two inequivalent Ba2+ sites. In the first Ba2+ site, Ba2+ is bonded to six As3- atoms to form distorted BaAs6 octahedra that share corners with six equivalent BaAs6 octahedra, corners with three equivalent TiAs4 tetrahedra, edges with twelve BaAs6 octahedra, and a faceface with one TiAs4 tetrahedra. The corner-sharing octahedra tilt angles range from 18–19°. There are three shorter (3.40 Å) and three longer (3.55 Å) Ba–As bond lengths. In the second Ba2+ site, Ba2+ is bonded to six As3- atoms to form distorted BaAs6 octahedra that share corners with six BaAs6 octahedra, corners with three TiAs4 tetrahedra, edges with twelve BaAs6 octahedra, and a faceface with one TiAs4 tetrahedra. The corner-sharing octahedra tilt angles range from 15–22°. There are a spread of Ba–As bond distances ranging from 3.35–3.58 Å. There are two inequivalent Ti4+ sites. In the first Ti4+ site, Ti4+ is bonded to four equivalent As3- atoms to form TiAs4 tetrahedra that share corners with twelve equivalent BaAs6 octahedra and faces with four equivalent BaAs6 octahedra. The corner-sharing octahedral tilt angles are 52°. All Ti–As bond lengths are 2.49 Å. In the second Ti4+ site, Ti4+ is bonded to four equivalent As3- atoms to form TiAs4 tetrahedra that share corners with twelve BaAs6 octahedra and faces with four equivalent BaAs6 octahedra. The corner-sharing octahedra tilt angles range from 45–55°. All Ti–As bond lengths are 2.50 Å. There are two inequivalent As3- sites. In the first As3- site, As3- is bonded in a 7-coordinate geometry to six Ba2+ and one Ti4+ atom. In the second As3- site, As3- is bonded in a 7-coordinate geometry to six Ba2+ and one Ti4+ atom.