Materials Data on Ba7Ga4As9 by Materials Project
Ba7Ga4As9 crystallizes in the orthorhombic Pmmn space group. The structure is three-dimensional. there are three inequivalent Ba2+ sites. In the first Ba2+ site, Ba2+ is bonded in a 6-coordinate geometry to six As+2.89- atoms. There are a spread of Ba–As bond distances ranging from 3.34–3.74 Å. In the second Ba2+ site, Ba2+ is bonded to seven As+2.89- atoms to form distorted BaAs7 pentagonal bipyramids that share corners with five equivalent BaAs7 pentagonal bipyramids, corners with five GaAs4 tetrahedra, edges with three equivalent BaAs7 pentagonal bipyramids, edges with two equivalent GaAs4 tetrahedra, faces with two equivalent BaAs7 pentagonal bipyramids, and a faceface with one GaAs4 tetrahedra. There are a spread of Ba–As bond distances ranging from 3.30–3.63 Å. In the third Ba2+ site, Ba2+ is bonded in a 5-coordinate geometry to five As+2.89- atoms. There are one shorter (3.14 Å) and four longer (3.26 Å) Ba–As bond lengths. There are two inequivalent Ga3+ sites. In the first Ga3+ site, Ga3+ is bonded to four As+2.89- atoms to form GaAs4 tetrahedra that share corners with six equivalent BaAs7 pentagonal bipyramids, corners with three GaAs4 tetrahedra, and faces with two equivalent BaAs7 pentagonal bipyramids. There are a spread of Ga–As bond distances ranging from 2.46–2.58 Å. In the second Ga3+ site, Ga3+ is bonded to four As+2.89- atoms to form GaAs4 tetrahedra that share corners with four equivalent BaAs7 pentagonal bipyramids, corners with two equivalent GaAs4 tetrahedra, edges with four equivalent BaAs7 pentagonal bipyramids, and an edgeedge with one GaAs4 tetrahedra. There are two shorter (2.53 Å) and two longer (2.58 Å) Ga–As bond lengths. There are five inequivalent As+2.89- sites. In the first As+2.89- site, As+2.89- is bonded in a 2-coordinate geometry to four equivalent Ba2+ and two equivalent Ga3+ atoms. In the second As+2.89- site, As+2.89- is bonded in a 6-coordinate geometry to four equivalent Ba2+ and two equivalent Ga3+ atoms. In the third As+2.89- site, As+2.89- is bonded in a distorted trigonal planar geometry to five Ba2+ and two equivalent Ga3+ atoms. In the fourth As+2.89- site, As+2.89- is bonded in a 7-coordinate geometry to five Ba2+ and two Ga3+ atoms. In the fifth As+2.89- site, As+2.89- is bonded in a 7-coordinate geometry to six Ba2+ and one Ga3+ atom.