Materials Data on NaCaMg3Fe6(PO4)9 by Materials Project
NaCaMg3Fe6(PO4)9 crystallizes in the monoclinic C2/c space group. The structure is three-dimensional. Na1+ is bonded in a 8-coordinate geometry to eight O2- atoms. There are a spread of Na–O bond distances ranging from 2.48–2.96 Å. Ca2+ is bonded in a distorted body-centered cubic geometry to eight O2- atoms. There are a spread of Ca–O bond distances ranging from 2.35–2.85 Å. 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 PO4 tetrahedra and edges with two FeO6 octahedra. There are a spread of Mg–O bond distances ranging from 2.11–2.18 Å. In the second Mg2+ site, Mg2+ is bonded to six O2- atoms to form distorted MgO6 octahedra that share corners with six PO4 tetrahedra and edges with two equivalent FeO6 octahedra. There are a spread of Mg–O bond distances ranging from 1.99–2.32 Å. There are three inequivalent Fe3+ sites. In the first Fe3+ site, Fe3+ is bonded to six O2- atoms to form distorted FeO6 octahedra that share corners with six PO4 tetrahedra, an edgeedge with one MgO6 octahedra, and an edgeedge with one FeO6 octahedra. There are a spread of Fe–O bond distances ranging from 1.92–2.24 Å. In the second Fe3+ site, Fe3+ is bonded to six O2- atoms to form FeO6 octahedra that share corners with six PO4 tetrahedra, an edgeedge with one MgO6 octahedra, and an edgeedge with one FeO6 octahedra. There are a spread of Fe–O bond distances ranging from 1.98–2.16 Å. In the third Fe3+ site, Fe3+ is bonded to six O2- atoms to form distorted FeO6 octahedra that share corners with six PO4 tetrahedra, an edgeedge with one MgO6 octahedra, and an edgeedge with one FeO6 octahedra. There are a spread of Fe–O bond distances ranging from 1.94–2.23 Å. There are five inequivalent P5+ sites. In the first P5+ site, P5+ is bonded to four O2- atoms to form PO4 tetrahedra that share corners with two equivalent MgO6 octahedra and corners with four FeO6 octahedra. The corner-sharing octahedra tilt angles range from 34–60°. There are a spread of P–O bond distances ranging from 1.53–1.58 Å. In the second P5+ site, P5+ is bonded to four O2- atoms to form PO4 tetrahedra that share corners with two MgO6 octahedra and corners with four FeO6 octahedra. The corner-sharing octahedra tilt angles range from 48–63°. There is one shorter (1.54 Å) and three longer (1.56 Å) P–O bond length. In the third P5+ site, P5+ is bonded to four O2- atoms to form PO4 tetrahedra that share corners with two MgO6 octahedra and corners with four FeO6 octahedra. The corner-sharing octahedra tilt angles range from 35–61°. There are a spread of P–O bond distances ranging from 1.53–1.57 Å. In the fourth P5+ site, P5+ is bonded to four O2- atoms to form PO4 tetrahedra that share corners with two MgO6 octahedra and corners with four FeO6 octahedra. The corner-sharing octahedra tilt angles range from 41–61°. There are a spread of P–O bond distances ranging from 1.50–1.58 Å. In the fifth P5+ site, P5+ is bonded to four O2- atoms to form PO4 tetrahedra that share corners with two equivalent MgO6 octahedra and corners with four FeO6 octahedra. The corner-sharing octahedra tilt angles range from 47–61°. There is two shorter (1.53 Å) and two longer (1.58 Å) P–O bond length. There are eighteen inequivalent O2- sites. In the first O2- site, O2- is bonded in a distorted trigonal planar geometry to one Mg2+, one Fe3+, and one P5+ atom. In the second O2- site, O2- is bonded in a 3-coordinate geometry to two Fe3+ and one P5+ atom. In the third O2- site, O2- is bonded in a distorted trigonal planar geometry to one Mg2+, one Fe3+, and one P5+ atom. In the fourth O2- site, O2- is bonded in a 2-coordinate geometry to one Ca2+, one Fe3+, and one P5+ atom. In the fifth O2- site, O2- is bonded in a bent 150 degrees geometry to one Fe3+ and one P5+ atom. In the sixth O2- site, O2- is bonded in a 3-coordinate geometry to one Ca2+, one Mg2+, and one P5+ atom. In the seventh O2- site, O2- is bonded in a 3-coordinate geometry to one Ca2+, one Mg2+, and one P5+ atom. In the eighth O2- site, O2- is bonded in a 3-coordinate geometry to one Na1+, one Fe3+, and one P5+ atom. In the ninth O2- site, O2- is bonded in a 3-coordinate geometry to one Ca2+, one Fe3+, and one P5+ atom. In the tenth O2- site, O2- is bonded in a 3-coordinate geometry to one Mg2+, one Fe3+, and one P5+ atom. In the eleventh O2- site, O2- is bonded in a distorted trigonal planar geometry to one Mg2+, one Fe3+, and one P5+ atom. In the twelfth O2- site, O2- is bonded in a 3-coordinate geometry to two equivalent Fe3+ and one P5+ atom. In the thirteenth O2- site, O2- is bonded in a 4-coordinate geometry to one Na1+, one Mg2+, one Fe3+, and one P5+ atom. In the fourteenth O2- site, O2- is bonded in a 3-coordinate geometry to two Fe3+ and one P5+ atom. In the fifteenth O2- site, O2- is bonded in a 3-coordinate geometry to one Na1+, one Mg2+, one Fe3+, and one P5+ atom. In the sixteenth O2- site, O2- is bonded in a distorted bent 120 degrees geometry to one Fe3+ and one P5+ atom. In the seventeenth O2- site, O2- is bonded in a 3-coordinate geometry to one Na1+, one Fe3+, and one P5+ atom. In the eighteenth O2- site, O2- is bonded in a distorted bent 120 degrees geometry to one Mg2+ and one P5+ atom.