DOE OSTI2020
Na2LiFeCPO7 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 2.27–2.77 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 2.27–2.70 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, and an edgeedge with one PO4 tetrahedra. The corner-sharing octahedral tilt angles are 69°. There are a spread of Na–O bond distances ranging from 2.37–2.84 Å. In the fourth 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 2.28–2.99 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 2.27–2.88 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 2.37–2.81 Å. In the seventh 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 2.31–2.85 Å. In the eighth 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 2.30–2.99 Å. There are four inequivalent Li1+ sites. In the first Li1+ site, Li1+ is bonded in a 4-coordinate geometry to four O2- atoms. There are a spread of Li–O bond distances ranging from 2.08–2.16 Å. In the second Li1+ site, Li1+ is bonded in a 4-coordinate geometry to five O2- atoms. There are a spread of Li–O bond distances ranging from 2.10–2.72 Å. In the third Li1+ site, Li1+ is bonded in a 5-coordinate geometry to five O2- atoms. There are a spread of Li–O bond distances ranging from 2.07–2.61 Å. In the fourth Li1+ site, Li1+ is bonded in a 4-coordinate geometry to four O2- atoms. There are a spread of Li–O bond distances ranging from 2.05–2.32 Å. There are four inequivalent Fe2+ sites. In the first Fe2+ site, Fe2+ is bonded to six O2- atoms to form distorted FeO6 octahedra that share corners with four PO4 tetrahedra and an edgeedge with one NaO7 pentagonal bipyramid. There are a spread of Fe–O bond distances ranging from 2.10–2.55 Å. In the second Fe2+ site, Fe2+ is bonded in a 6-coordinate geometry to six O2- atoms. There are a spread of Fe–O bond distances ranging from 2.11–2.55 Å. In the third Fe2+ site, Fe2+ is bonded to six O2- atoms to form distorted 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 2.12–2.32 Å. In the fourth Fe2+ site, Fe2+ is bonded to six O2- atoms to form distorted FeO6 octahedra that share corners with four PO4 tetrahedra. There are a spread of Fe–O bond distances ranging from 2.13–2.29 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 is two shorter (1.30 Å) and one 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 is two shorter (1.30 Å) and one longer (1.31 Å) C–O bond length. In the third C4+ site, C4+ is bonded in a trigonal planar geometry to three O2- atoms. There is two shorter (1.30 Å) and one longer (1.31 Å) C–O bond length. In the fourth 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 1.29–1.31 Å. 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 and an edgeedge with one NaO7 pentagonal bipyramid. The corner-sharing octahedra tilt angles range from 39–62°. There are a spread of P–O bond distances ranging from 1.55–1.57 Å. In the second P5+ site, P5+ is bonded to four O2- atoms to form PO4 tetrahedra that share corners with two FeO6 octahedra and a cornercorner with one NaO7 pentagonal bipyramid. The corner-sharing octahedra tilt angles range from 44–55°. There are a spread of P–O bond distances ranging from 1.54–1.57 Å. In the third P5+ site, P5+ is bonded to four O2- atoms to form PO4 tetrahedra that share corners with three FeO6 octahedra and a cornercorner with one NaO7 pentagonal bipyramid. The corner-sharing octahedra tilt angles range from 40–60°. There is one shorter (1.55 Å) and three 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 three FeO6 octahedra. The corner-sharing octahedra tilt angles range from 41–49°. There are a spread of P–O bond distances ranging from 1.54–1.57 Å. There are twenty-eight inequivalent O2- sites. In the first O2- site, O2- is bonded in a 5-coordinate geometry to three Na1+, one Li1+, and one C4+ atom. In the second O2- site, O2- is bonded in a 5-coordinate geometry to four Na1+ and one C4+ atom. In the third O2- site, O2- is bonded in a distorted bent 120 degrees geometry to two Na1+, one Li1+, one Fe2+, and one C4+ atom. In the fourth O2- site, O2- is bonded in a distorted bent 120 degrees geometry to one Na1+, one Li1+, one Fe2+, and one C4+ atom. In the fifth O2- site, O2- is bonded in a 1-coordinate geometry to one Na1+, one Li1+, one Fe2+, and one C4+ atom. In the sixth O2- site, O2- is bonded in a 4-coordinate geometry to two Na1+, one Fe2+, and one C4+ atom. In the seventh O2- site, O2- is bonded in a 4-coordinate geometry to two Na1+, one Fe2+, and one P5+ atom. In the eighth O2- site, O2- is bonded in a 1-coordinate geometry to three Na1+, one Fe2+, and one P5+ atom. In the ninth O2- site, O2- is bonded in a 4-coordinate geometry to two Na1+, one Li1+, one Fe2+, and one P5+ atom. In the tenth O2- site, O2- is bonded in a 1-coordinate geometry to three Na1+, one Fe2+, and one P5+ atom. In the eleventh O2- site, O2- is bonded in a distorted tetrahedral geometry to one Na1+, one Li1+, one Fe2+, and one P5+ atom. In the twelfth O2- site, O2- is bonded in a 4-coordinate geometry to one Na1+, one Li1+, one Fe2+, and one P5+ atom. In the thirteenth O2- site, O2- is bonded in a distorted tetrahedral geometry to two Na1+, one Fe2+, and one P5+ atom. In the fourteenth O2- site, O2- is bonded in a rectangular see-saw-like geometry to two Na1+, one Fe2+, and one P5+ atom. In the fifteenth O2- site, O2- is bonded in a 4-coordinate geometry to one Na1+, one Li1+, one Fe2+, and one P5+ atom. In the sixteenth O2- site, O2- is bonded in a 4-coordinate geometry to one Na1+, one Li1+, one Fe2+, and one P5+ atom. In the seventeenth O2- site, O2- is bonded in a distorted rectangular see-saw-like geometry to two Na1+, one Fe2+, and one P5+ atom. In the eighteenth O2- site, O2- is bonded in a 4-coordinate geometry to two Na1+, one Fe2+, and one P5+ atom. In the nineteenth O2- site, O2- is bonded in a 1-coordinate geometry to two Na1+, one Li1+, one Fe2+, and one P5+ atom. In the twentieth O2- site, O2- is bonded in a 4-coordinate geometry to one Na1+, one Li1+, one Fe2+, and one P5+ atom. In the twenty-first O2- site, O2- is bonded in a 1-coordinate geometry to two Na1+, one Li1+, one Fe2+, and one P5+ atom. In the twenty-second O2- site, O2- is bonded in a 4-coordinate geometry to one Na1+, two Li1+, one Fe2+, and one P5+ atom. In the twenty-third O2- site, O2- is bonded in a 1-coordinate geometry to two Na1+, one Li1+, one Fe2+, and one C4+ atom. In the twenty-fourth O2- site, O2- is bonded in a 5-coordinate geometry to three Na1+, one Fe2+, and one C4+ atom. In the twenty-fifth O2- site, O2- is bonded in a 1-coordinate geometry to three Na1+, one Fe2+, and one C4+ atom. In the twenty-sixth O2- site, O2- is bonded in a 1-coordinate geometry to two Na1+, one Fe2+, and one C4+ atom. In the twenty-seventh O2- site, O2- is bonded in a distorted tetrahedral geometry to one Na1+, two Li1+, and one C4+ atom. In the twenty-eighth O2- site, O2- is bonded in a distorted tetrahedral geometry to two Na1+, one Li1+, and one C4+ atom.