Materials Data on Sr3(AlP2)2 by Materials Project

Abstract

Sr3(AlP2)2 crystallizes in the monoclinic C2/c space group. The structure is three-dimensional. there are two inequivalent Sr2+ sites. In the first Sr2+ site, Sr2+ is bonded to six P3- atoms to form distorted SrP6 octahedra that share corners with seven SrP6 octahedra, corners with six equivalent AlP4 tetrahedra, edges with six equivalent SrP6 octahedra, edges with three equivalent AlP4 tetrahedra, and a faceface with one SrP6 octahedra. The corner-sharing octahedra tilt angles range from 17–64°. There are a spread of Sr–P bond distances ranging from 3.02–3.52 Å. In the second Sr2+ site, Sr2+ is bonded to six P3- atoms to form SrP6 octahedra that share corners with ten equivalent SrP6 octahedra, corners with four equivalent AlP4 tetrahedra, edges with two equivalent SrP6 octahedra, edges with four equivalent AlP4 tetrahedra, and faces with two equivalent SrP6 octahedra. The corner-sharing octahedra tilt angles range from 29–64°. There are four shorter (3.04 Å) and two longer (3.18 Å) Sr–P bond lengths. Al3+ is bonded to four P3- atoms to form AlP4 tetrahedra that share corners with eight SrP6 octahedra, corners with two equivalent AlP4 tetrahedra, edges with five SrP6 octahedra, and an edgeedge with one AlP4 tetrahedra. The corner-sharing octahedra tilt angles range from 22–85°. There are a spread of Al–P bond distances ranging from 2.39–2.45 Å. There are two inequivalent P3- sites. In the first P3- site, P3- is bonded in a 7-coordinate geometry to five Sr2+ and two equivalent Al3+ atoms. In the second P3- site, P3- is bonded in a 6-coordinate geometry to four Sr2+ and two equivalent Al3+ atoms.