DOE OSTI2020
Na2FeCPO7 crystallizes in the triclinic P1 space group. The structure is three-dimensional. there are eight 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 2.37–2.80 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 2.36–2.79 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 64°. There are a spread of Na–O bond distances ranging from 2.24–2.66 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 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 66°. There are a spread of Na–O bond distances ranging from 2.23–2.68 Å. In the fifth Na1+ site, Na1+ is bonded in a 7-coordinate geometry to seven O2- atoms. There are a spread of Na–O bond distances ranging from 2.24–2.82 Å. In the sixth Na1+ site, Na1+ is bonded in a 7-coordinate geometry to seven O2- atoms. There are a spread of Na–O bond distances ranging from 2.24–2.82 Å. In the seventh 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 2.33–2.89 Å. In the eighth 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. There are four inequivalent Fe3+ sites. In the first Fe3+ site, Fe3+ is bonded to six O2- atoms to form distorted FeO6 octahedra that share corners with four PO4 tetrahedra and faces with two NaO7 pentagonal bipyramids. There are a spread of Fe–O bond distances ranging from 1.96–2.19 Å. In the second Fe3+ site, Fe3+ is bonded to six O2- atoms to form distorted FeO6 octahedra that share corners with four PO4 tetrahedra and edges with two NaO7 pentagonal bipyramids. There are a spread of Fe–O bond distances ranging from 1.93–2.24 Å. In the third Fe3+ site, Fe3+ is bonded to six O2- atoms to form FeO6 octahedra that share a cornercorner with one NaO7 pentagonal bipyramid and corners with four PO4 tetrahedra. There are a spread of Fe–O bond distances ranging from 1.97–2.14 Å. In the fourth Fe3+ site, Fe3+ is bonded to six O2- atoms to form FeO6 octahedra that share a cornercorner with one NaO7 pentagonal bipyramid and corners with four PO4 tetrahedra. There are a spread of Fe–O bond distances ranging from 1.98–2.14 Å. There are four inequivalent C4+ sites. In the first 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. 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. In the third 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. In the fourth 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. There are four 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, a cornercorner with one NaO7 pentagonal bipyramid, and an edgeedge with one NaO7 pentagonal bipyramid. The corner-sharing octahedra tilt angles range from 33–44°. There is one shorter (1.54 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 33–46°. There are a spread of P–O bond distances ranging from 1.54–1.56 Å. In the third P5+ site, P5+ is bonded to four O2- atoms to form PO4 tetrahedra that share corners with four FeO6 octahedra and corners with two NaO7 pentagonal bipyramids. The corner-sharing octahedra tilt angles range from 35–43°. There is two shorter (1.55 Å) and two longer (1.56 Å) P–O bond length. In the fourth P5+ site, P5+ is bonded to four O2- atoms to form PO4 tetrahedra that share corners with four FeO6 octahedra. The corner-sharing octahedra tilt angles range from 33–49°. There are a spread of P–O bond distances ranging from 1.54–1.56 Å. There are twenty-eight 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 distorted T-shaped 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 bent 150 degrees geometry to one Fe3+ and one P5+ atom. In the twelfth O2- site, O2- is bonded in a distorted rectangular see-saw-like geometry to two Na1+, 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. In the fifteenth O2- site, O2- is bonded in a 3-coordinate geometry to one Na1+, one Fe3+, and one P5+ atom. In the sixteenth O2- site, O2- is bonded in a distorted trigonal planar geometry to one Na1+, 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 3-coordinate geometry to one Na1+, one Fe3+, and one P5+ atom. In the nineteenth O2- site, O2- is bonded in a 1-coordinate geometry to three Na1+, one Fe3+, and one P5+ atom. In the twentieth O2- site, O2- is bonded in a 3-coordinate geometry to one Na1+, one Fe3+, and one P5+ atom. In the twenty-first O2- site, O2- is bonded in a 1-coordinate geometry to three Na1+, one Fe3+, and one P5+ atom. In the twenty-second O2- site, O2- is bonded in a 3-coordinate geometry to one Na1+, one Fe3+, and one P5+ atom. In the twenty-third O2- site, O2- is bonded in a 1-coordinate geometry to two Na1+, one Fe3+, and one C4+ atom. In the twenty-fourth O2- site, O2- is bonded in a 1-coordinate geometry to two Na1+, one Fe3+, and one C4+ atom. In the twenty-fifth O2- site, O2- is bonded in a 1-coordinate geometry to two Na1+, one Fe3+, and one C4+ atom. In the twenty-sixth O2- site, O2- is bonded in a 4-coordinate geometry to two Na1+, one Fe3+, and one C4+ atom. In the twenty-seventh O2- site, O2- is bonded in a 4-coordinate geometry to three Na1+ and one C4+ atom. In the twenty-eighth O2- site, O2- is bonded in a 4-coordinate geometry to three Na1+ and one C4+ atom.