Materials Data on Mg3(PO4)2 by Materials Project

Abstract

Mg3(PO4)2 crystallizes in the monoclinic P2_1/c space group. The structure is three-dimensional. there are two inequivalent Mg2+ sites. In the first Mg2+ site, Mg2+ is bonded to six O2- atoms to form distorted MgO6 octahedra that share corners with six MgO6 octahedra, corners with four equivalent PO4 tetrahedra, an edgeedge with one MgO6 octahedra, and an edgeedge with one PO4 tetrahedra. The corner-sharing octahedra tilt angles range from 51–63°. There are a spread of Mg–O bond distances ranging from 2.03–2.27 Å. In the second Mg2+ site, Mg2+ is bonded to six O2- atoms to form MgO6 octahedra that share corners with four equivalent MgO6 octahedra, corners with two equivalent PO4 tetrahedra, edges with two equivalent MgO6 octahedra, and edges with two equivalent PO4 tetrahedra. The corner-sharing octahedra tilt angles range from 58–63°. There are a spread of Mg–O bond distances ranging from 2.10–2.14 Å. P5+ is bonded to four O2- atoms to form PO4 tetrahedra that share corners with five MgO6 octahedra and edges with two MgO6 octahedra. The corner-sharing octahedra tilt angles range from 47–58°. There are a spread of P–O bond distances ranging from 1.54–1.60 Å. There are four inequivalent O2- sites. In the first O2- site, O2- is bonded in a distorted trigonal planar geometry to two Mg2+ and one P5+ atom. In the second O2- site, O2- is bonded in a distorted trigonal planar geometry to two Mg2+ and one P5+ atom. In the third O2- site, O2- is bonded in a distorted rectangular see-saw-like geometry to three Mg2+ and one P5+ atom. In the fourth O2- site, O2- is bonded in a distorted trigonal planar geometry to two equivalent Mg2+ and one P5+ atom.