Materials Data on Na2FeNi2(PO4)3 by Materials Project
Na2Ni2Fe(PO4)3 crystallizes in the monoclinic C2/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 2.30–2.87 Å. In the second 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 2.40–2.91 Å. Fe3+ is bonded to six O2- atoms to form distorted FeO6 octahedra that share corners with six PO4 tetrahedra and edges with two equivalent NiO6 octahedra. There are a spread of Fe–O bond distances ranging from 2.06–2.13 Å. Ni2+ is bonded to six O2- atoms to form NiO6 octahedra that share corners with six PO4 tetrahedra, an edgeedge with one FeO6 octahedra, and an edgeedge with one NiO6 octahedra. There are a spread of Ni–O bond distances ranging from 1.96–2.13 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 two equivalent FeO6 octahedra and corners with four equivalent NiO6 octahedra. The corner-sharing octahedra tilt angles range from 53–60°. There is two shorter (1.53 Å) and two longer (1.59 Å) P–O bond length. In the second P5+ site, P5+ is bonded to four O2- atoms to form PO4 tetrahedra that share corners with two equivalent FeO6 octahedra and corners with four equivalent NiO6 octahedra. The corner-sharing octahedra tilt angles range from 38–59°. There are a spread of P–O bond distances ranging from 1.54–1.59 Å. There are six inequivalent O2- sites. In the first O2- site, O2- is bonded in a 3-coordinate geometry to one Na1+, one Fe3+, one Ni2+, and one P5+ atom. In the second O2- site, O2- is bonded in a 4-coordinate geometry to two equivalent Na1+, one Ni2+, and one P5+ atom. In the third O2- site, O2- is bonded in a 3-coordinate geometry to two equivalent Ni2+ and one P5+ atom. In the fourth O2- site, O2- is bonded in a 3-coordinate geometry to one Na1+, one Fe3+, one Ni2+, and one P5+ atom. In the fifth O2- site, O2- is bonded in a 3-coordinate geometry to two equivalent Na1+, one Ni2+, and one P5+ atom. In the sixth O2- site, O2- is bonded in a 4-coordinate geometry to two equivalent Na1+, one Fe3+, and one P5+ atom.