DOI: 10.17188/1298829
title: Materials Data on Na2FePCO7 by Materials Project

description: Na2FeCPO7 crystallizes in the triclinic P-1 space group. The structure is three-dimensional. there are four inequivalent Na1+ sites. In the first Na1+ site, Na1+ is bonded in a 6-coordinate geometry to six O2- atoms. There are a spread of Na–O bond distances ranging from 2.35–2.85 Å. In the second Na1+ site, Na1+ is bonded in a 6-coordinate geometry to six O2- atoms. There are a spread of Na–O bond distances ranging from 2.39–2.71 Å. In the third Na1+ site, Na1+ is bonded to seven O2- atoms to form distorted NaO7 pentagonal bipyramids that share a cornercorner with one FeO6 octahedra, corners with two PO4 tetrahedra, an edgeedge with one FeO6 octahedra, an edgeedge with one PO4 tetrahedra, a faceface with one FeO6 octahedra, and a faceface with one NaO7 pentagonal bipyramid. The corner-sharing octahedral tilt angles are 67°. There are a spread of Na–O bond distances ranging from 2.24–2.67 Å. In the fourth Na1+ site, Na1+ is bonded to seven O2- atoms to form distorted NaO7 pentagonal bipyramids that share a cornercorner with one FeO6 octahedra, corners with two equivalent PO4 tetrahedra, an edgeedge with one FeO6 octahedra, an edgeedge with one PO4 tetrahedra, a faceface with one FeO6 octahedra, and a faceface with one NaO7 pentagonal bipyramid. The corner-sharing octahedral tilt angles are 63°. There are a spread of Na–O bond distances ranging from 2.24–2.69 Å. There are two inequivalent Fe3+ sites. In the first Fe3+ site, Fe3+ is bonded to six O2- atoms to form distorted FeO6 octahedra that share a cornercorner with one NaO7 pentagonal bipyramid, corners with four PO4 tetrahedra, and edges with two NaO7 pentagonal bipyramids. There are a spread of Fe–O bond distances ranging from 1.91–2.27 Å. In the second Fe3+ site, Fe3+ is bonded to six O2- atoms to form distorted FeO6 octahedra that share a cornercorner with one NaO7 pentagonal bipyramid, corners with four PO4 tetrahedra, and faces with two NaO7 pentagonal bipyramids. There are a spread of Fe–O bond distances ranging from 1.94–2.21 Å. There are two inequivalent C4+ sites. In the first C4+ site, C4+ is bonded in a trigonal planar geometry to three O2- atoms. There is one shorter (1.27 Å) and two longer (1.31 Å) C–O bond length. In the second C4+ site, C4+ is bonded in a trigonal planar geometry to three O2- atoms. There are a spread of C–O bond distances ranging from 1.27–1.32 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 four FeO6 octahedra, corners with three NaO7 pentagonal bipyramids, and an edgeedge with one NaO7 pentagonal bipyramid. The corner-sharing octahedra tilt angles range from 35–43°. There is one shorter (1.55 Å) and three longer (1.56 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 four FeO6 octahedra, a cornercorner with one NaO7 pentagonal bipyramid, and an edgeedge with one NaO7 pentagonal bipyramid. The corner-sharing octahedra tilt angles range from 33–48°. There are a spread of P–O bond distances ranging from 1.53–1.56 Å. There are fourteen inequivalent O2- sites. In the first O2- site, O2- is bonded in a 4-coordinate geometry to three Na1+ and one C4+ atom. In the second O2- site, O2- is bonded in a 4-coordinate geometry to three Na1+ and one C4+ atom. In the third O2- site, O2- is bonded in a 3-coordinate geometry to one Na1+, one Fe3+, and one C4+ atom. In the fourth O2- site, O2- is bonded in a 1-coordinate geometry to three Na1+, one Fe3+, and one C4+ atom. In the fifth O2- site, O2- is bonded in a 1-coordinate geometry to three Na1+, one Fe3+, and one C4+ atom. In the sixth O2- site, O2- is bonded in a 3-coordinate geometry to one Na1+, one Fe3+, and one C4+ atom. In the seventh O2- site, O2- is bonded in a 4-coordinate geometry to two Na1+, one Fe3+, and one P5+ atom. In the eighth O2- site, O2- is bonded in a 4-coordinate geometry to two Na1+, one Fe3+, and one P5+ atom. In the ninth O2- site, O2- is bonded in a 4-coordinate geometry to two Na1+, one Fe3+, and one P5+ atom. In the tenth O2- site, O2- is bonded in a 4-coordinate geometry to two Na1+, one Fe3+, and one P5+ atom. In the eleventh O2- site, O2- is bonded in a distorted rectangular see-saw-like geometry to two Na1+, one Fe3+, and one P5+ atom. In the twelfth O2- site, O2- is bonded in a bent 150 degrees geometry to one Fe3+ and one P5+ atom. In the thirteenth O2- site, O2- is bonded in a 3-coordinate geometry to one Na1+, one Fe3+, and one P5+ atom. In the fourteenth O2- site, O2- is bonded in a 3-coordinate geometry to one Na1+, one Fe3+, and one P5+ atom.