Materials Data on Na2CaMg(PO4)2 by Materials Project

Abstract

Na2CaMg(PO4)2 crystallizes in the monoclinic P2_1/c space group. The structure is three-dimensional. there are two inequivalent Na1+ sites. In the first Na1+ site, Na1+ is bonded in a 8-coordinate geometry to eight O2- atoms. There are a spread of Na–O bond distances ranging from 2.28–2.79 Å. In the second Na1+ site, Na1+ is bonded in a 9-coordinate geometry to nine O2- atoms. There are a spread of Na–O bond distances ranging from 2.29–2.96 Å. Ca2+ is bonded in a 8-coordinate geometry to eight O2- atoms. There are a spread of Ca–O bond distances ranging from 2.38–2.97 Å. Mg2+ is bonded to six O2- atoms to form MgO6 octahedra that share corners with six PO4 tetrahedra. There are a spread of Mg–O bond distances ranging from 2.06–2.14 Å. There are two inequivalent P5+ sites. In the first P5+ site, P5+ is bonded to four O2- atoms to form PO4 tetrahedra that share corners with three equivalent MgO6 octahedra. The corner-sharing octahedra tilt angles range from 16–45°. There are a spread of P–O bond distances ranging from 1.53–1.57 Å. In the second P5+ site, P5+ is bonded to four O2- atoms to form PO4 tetrahedra that share corners with three equivalent MgO6 octahedra. The corner-sharing octahedra tilt angles range from 3–41°. There is one shorter (1.53 Å) and three longer (1.56 Å) P–O bond length. There are eight inequivalent O2- sites. In the first O2- site, O2- is bonded in a 5-coordinate geometry to two Na1+, one Ca2+, one Mg2+, and one P5+ atom. In the second O2- site, O2- is bonded in a 5-coordinate geometry to two Na1+, one Ca2+, one Mg2+, and one P5+ atom. In the third O2- site, O2- is bonded in a 2-coordinate geometry to two equivalent Na1+, one Ca2+, one Mg2+, and one P5+ atom. In the fourth O2- site, O2- is bonded in a 6-coordinate geometry to three Na1+, one Ca2+, one Mg2+, and one P5+ atom. In the fifth O2- site, O2- is bonded in a 3-coordinate geometry to one Na1+, one Ca2+, and one P5+ atom. In the sixth O2- site, O2- is bonded in a 5-coordinate geometry to three Na1+, one Mg2+, and one P5+ atom. In the seventh O2- site, O2- is bonded in a 1-coordinate geometry to one Na1+, two equivalent Ca2+, and one P5+ atom. In the eighth O2- site, O2- is bonded in a 2-coordinate geometry to three equivalent Na1+, one Ca2+, one Mg2+, and one P5+ atom.