Materials Data on Ca3(AlP2)2 by Materials Project

Abstract

Ca3Al2P4 crystallizes in the monoclinic C2/c space group. The structure is three-dimensional. there are two inequivalent Ca2+ sites. In the first Ca2+ site, Ca2+ is bonded to six P3- atoms to form distorted CaP6 octahedra that share corners with seven CaP6 octahedra, corners with six equivalent AlP4 tetrahedra, edges with six equivalent CaP6 octahedra, edges with three equivalent AlP4 tetrahedra, and a faceface with one CaP6 octahedra. The corner-sharing octahedra tilt angles range from 15–58°. There are a spread of Ca–P bond distances ranging from 2.85–3.31 Å. In the second Ca2+ site, Ca2+ is bonded to six P3- atoms to form CaP6 octahedra that share corners with ten equivalent CaP6 octahedra, corners with four equivalent AlP4 tetrahedra, edges with two equivalent CaP6 octahedra, edges with four equivalent AlP4 tetrahedra, and faces with two equivalent CaP6 octahedra. The corner-sharing octahedra tilt angles range from 35–58°. There are a spread of Ca–P bond distances ranging from 2.84–3.05 Å. Al3+ is bonded to four P3- atoms to form AlP4 tetrahedra that share corners with eight CaP6 octahedra, corners with two equivalent AlP4 tetrahedra, edges with five CaP6 octahedra, and an edgeedge with one AlP4 tetrahedra. The corner-sharing octahedra tilt angles range from 20–83°. There are a spread of Al–P bond distances ranging from 2.37–2.42 Å. There are two inequivalent P3- sites. In the first P3- site, P3- is bonded in a 7-coordinate geometry to five Ca2+ and two equivalent Al3+ atoms. In the second P3- site, P3- is bonded in a 6-coordinate geometry to four Ca2+ and two equivalent Al3+ atoms.