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All sourcesNASA NTRSDOE OSTI
DOE OSTI2020

Materials Data on Ba3AlAs3 by Materials Project

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.

36 MATERIALS SCIENCE↗
DOE OSTI2020

Materials Data on Ba3(AlAs2)2 by Materials Project

Ba3Al2As4 crystallizes in the orthorhombic Pnma 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 pentagonal pyramids that share corners with four equivalent BaAs6 octahedra, corners with four equivalent BaAs6 pentagonal pyramids, corners with six equivalent AlAs4 tetrahedra, edges with two equivalent BaAs6 octahedra, edges with three equivalent BaAs6 pentagonal pyramids, edges with three equivalent AlAs4 tetrahedra, and a faceface with one BaAs6 pentagonal pyramid. The corner-sharing octahedra tilt angles range from 38–89°. There are a spread of Ba–As bond distances ranging from 3.25–3.61 Å. In the second Ba2+ site, Ba2+ is bonded to six As3- atoms to form BaAs6 octahedra that share corners with eight equivalent BaAs6 pentagonal pyramids, corners with eight equivalent AlAs4 tetrahedra, edges with four equivalent BaAs6 pentagonal pyramids, edges with two equivalent AlAs4 tetrahedra, and faces with two equivalent BaAs6 octahedra. There are a spread of Ba–As bond distances ranging from 3.26–3.47 Å. Al3+ is bonded to four As3- atoms to form AlAs4 tetrahedra that share corners with four equivalent BaAs6 octahedra, corners with six equivalent BaAs6 pentagonal pyramids, an edgeedge with one BaAs6 octahedra, edges with three equivalent BaAs6 pentagonal pyramids, and edges with two equivalent AlAs4 tetrahedra. The corner-sharing octahedra tilt angles range from 20–62°. There are a spread of Al–As bond distances ranging from 2.50–2.57 Å. There are three inequivalent As3- sites. In the first As3- site, As3- is bonded in a 6-coordinate geometry to four equivalent Ba2+ and two equivalent Al3+ atoms. In the second As3- site, As3- is bonded in a 7-coordinate geometry to five Ba2+ and two equivalent Al3+ atoms. In the third As3- site, As3- is bonded in a 6-coordinate geometry to four Ba2+ and two equivalent Al3+ atoms.

36 MATERIALS SCIENCE↗
DOE OSTI2020

Materials Data on Ba3Al3As5 by Materials Project

Ba3Al3As5 crystallizes in the trigonal R-3c space group. The structure is three-dimensional. there are three inequivalent Ba2+ sites. In the first Ba2+ site, Ba2+ is bonded in a 7-coordinate geometry to seven As3- atoms. There are a spread of Ba–As bond distances ranging from 3.27–3.86 Å. In the second Ba2+ site, Ba2+ is bonded in a 6-coordinate geometry to six As3- atoms. There are three shorter (3.29 Å) and three longer (3.72 Å) Ba–As bond lengths. In the third Ba2+ site, Ba2+ is bonded to six equivalent As3- atoms to form distorted BaAs6 octahedra that share corners with twelve equivalent AlAs4 tetrahedra and edges with three equivalent AlAs4 tetrahedra. All Ba–As bond lengths are 3.26 Å. There are two inequivalent Al3+ sites. In the first Al3+ site, Al3+ is bonded to four As3- atoms to form AlAs4 tetrahedra that share corners with two equivalent AlAs4 tetrahedra, an edgeedge with one BaAs6 octahedra, and edges with two equivalent AlAs4 tetrahedra. There are two shorter (2.50 Å) and two longer (2.58 Å) Al–As bond lengths. In the second Al3+ site, Al3+ is bonded to four As3- atoms to form AlAs4 tetrahedra that share corners with two equivalent BaAs6 octahedra, corners with two AlAs4 tetrahedra, and edges with two AlAs4 tetrahedra. The corner-sharing octahedra tilt angles range from 24–65°. There are a spread of Al–As bond distances ranging from 2.44–2.59 Å. There are three inequivalent As3- sites. In the first As3- site, As3- is bonded in a 2-coordinate geometry to four equivalent Ba2+ and two equivalent Al3+ atoms. In the second As3- site, As3- is bonded in a 7-coordinate geometry to four Ba2+ and three Al3+ atoms. In the third As3- site, As3- is bonded in a 6-coordinate geometry to four Ba2+ and two Al3+ atoms.

36 MATERIALS SCIENCE↗