Materials Data on Ba3(AlP2)2 by Materials Project

Abstract

Ba3Al2P4 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 P3- atoms to form distorted BaP6 pentagonal pyramids that share corners with four equivalent BaP6 octahedra, corners with four equivalent BaP6 pentagonal pyramids, corners with six equivalent AlP4 tetrahedra, edges with two equivalent BaP6 octahedra, edges with three equivalent BaP6 pentagonal pyramids, edges with three equivalent AlP4 tetrahedra, and a faceface with one BaP6 pentagonal pyramid. The corner-sharing octahedra tilt angles range from 39–88°. There are a spread of Ba–P bond distances ranging from 3.17–3.56 Å. In the second Ba2+ site, Ba2+ is bonded to six P3- atoms to form BaP6 octahedra that share corners with eight equivalent BaP6 pentagonal pyramids, corners with eight equivalent AlP4 tetrahedra, edges with four equivalent BaP6 pentagonal pyramids, edges with two equivalent AlP4 tetrahedra, and faces with two equivalent BaP6 octahedra. There are a spread of Ba–P bond distances ranging from 3.19–3.43 Å. Al3+ is bonded to four P3- atoms to form AlP4 tetrahedra that share corners with four equivalent BaP6 octahedra, corners with six equivalent BaP6 pentagonal pyramids, an edgeedge with one BaP6 octahedra, edges with three equivalent BaP6 pentagonal pyramids, and edges with two equivalent AlP4 tetrahedra. The corner-sharing octahedra tilt angles range from 19–64°. There are a spread of Al–P bond distances ranging from 2.39–2.47 Å. There are three inequivalent P3- sites. In the first P3- site, P3- is bonded in a 6-coordinate geometry to four equivalent Ba2+ and two equivalent Al3+ atoms. In the second P3- site, P3- is bonded in a 7-coordinate geometry to five Ba2+ and two equivalent Al3+ atoms. In the third P3- site, P3- is bonded in a 6-coordinate geometry to four Ba2+ and two equivalent Al3+ atoms.