DOE OSTI2020
LiFeP2O7 crystallizes in the triclinic P1 space group. The structure is three-dimensional. there are eight 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 1.89–2.31 Å. In the second Li1+ site, Li1+ is bonded to four O2- atoms to form distorted LiO4 trigonal pyramids that share a cornercorner with one FeO6 octahedra and corners with four PO4 tetrahedra. The corner-sharing octahedral tilt angles are 54°. There are a spread of Li–O bond distances ranging from 1.88–2.02 Å. In the third Li1+ site, Li1+ is bonded to five O2- atoms to form distorted LiO5 trigonal bipyramids that share corners with five PO4 tetrahedra and an edgeedge with one FeO6 octahedra. There are a spread of Li–O bond distances ranging from 1.81–2.54 Å. In the fourth 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 1.96–2.45 Å. In the fifth 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 1.84–2.61 Å. In the sixth Li1+ site, Li1+ is bonded to four O2- atoms to form distorted LiO4 tetrahedra that share a cornercorner with one FeO6 octahedra and corners with four PO4 tetrahedra. The corner-sharing octahedral tilt angles are 73°. There are a spread of Li–O bond distances ranging from 1.88–2.06 Å. In the seventh 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 1.82–2.18 Å. In the eighth 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 1.95–2.25 Å. There are eight inequivalent Fe3+ sites. In the first Fe3+ site, Fe3+ is bonded to six O2- atoms to form FeO6 octahedra that share corners with six PO4 tetrahedra, an edgeedge with one LiO5 trigonal bipyramid, and an edgeedge with one FeO5 trigonal bipyramid. There are a spread of Fe–O bond distances ranging from 1.95–2.17 Å. In the second Fe3+ site, Fe3+ is bonded to five O2- atoms to form distorted FeO5 trigonal bipyramids that share corners with five PO4 tetrahedra and an edgeedge with one FeO6 octahedra. There are a spread of Fe–O bond distances ranging from 1.88–2.16 Å. In the third Fe3+ site, Fe3+ is bonded in a 6-coordinate geometry to six O2- atoms. There are a spread of Fe–O bond distances ranging from 1.92–2.54 Å. In the fourth Fe3+ site, Fe3+ is bonded to six O2- atoms to form FeO6 octahedra that share corners with six PO4 tetrahedra. There are a spread of Fe–O bond distances ranging from 1.91–2.23 Å. In the fifth Fe3+ site, Fe3+ is bonded to six O2- atoms to form FeO6 octahedra that share corners with six PO4 tetrahedra. There are a spread of Fe–O bond distances ranging from 1.92–2.22 Å. In the sixth Fe3+ site, Fe3+ is bonded in a 5-coordinate geometry to five O2- atoms. There are a spread of Fe–O bond distances ranging from 1.92–2.24 Å. In the seventh Fe3+ site, Fe3+ is bonded to six O2- atoms to form distorted FeO6 octahedra that share a cornercorner with one LiO4 tetrahedra, corners with four PO4 tetrahedra, a cornercorner with one LiO4 trigonal pyramid, an edgeedge with one FeO6 octahedra, and an edgeedge with one PO4 tetrahedra. There are a spread of Fe–O bond distances ranging from 1.99–2.52 Å. In the eighth Fe3+ site, Fe3+ is bonded to six O2- atoms to form FeO6 octahedra that share corners with six PO4 tetrahedra and an edgeedge with one FeO6 octahedra. There are a spread of Fe–O bond distances ranging from 1.98–2.18 Å. There are sixteen inequivalent P5+ sites. In the first P5+ site, P5+ is bonded to four O2- atoms to form PO4 tetrahedra that share a cornercorner with one FeO6 octahedra, a cornercorner with one PO4 tetrahedra, and a cornercorner with one FeO5 trigonal bipyramid. The corner-sharing octahedral tilt angles are 54°. There are a spread of P–O bond distances ranging from 1.51–1.60 Å. In the second P5+ site, P5+ is bonded to four O2- atoms to form PO4 tetrahedra that share a cornercorner with one FeO6 octahedra, a cornercorner with one LiO4 tetrahedra, a cornercorner with one PO4 tetrahedra, and a cornercorner with one LiO4 trigonal pyramid. The corner-sharing octahedral tilt angles are 32°. There are a spread of P–O bond distances ranging from 1.50–1.62 Å. In the third P5+ site, P5+ is bonded to four O2- atoms to form PO4 tetrahedra that share corners with two FeO6 octahedra, a cornercorner with one LiO4 tetrahedra, a cornercorner with one PO4 tetrahedra, and a cornercorner with one LiO5 trigonal bipyramid. The corner-sharing octahedra tilt angles range from 51–55°. There are a spread of P–O bond distances ranging from 1.50–1.61 Å. In the fourth P5+ site, P5+ is bonded to four O2- atoms to form PO4 tetrahedra that share corners with three FeO6 octahedra, a cornercorner with one PO4 tetrahedra, and a cornercorner with one LiO5 trigonal bipyramid. The corner-sharing octahedra tilt angles range from 31–52°. There are a spread of P–O bond distances ranging from 1.52–1.61 Å. In the fifth P5+ site, P5+ is bonded to four O2- atoms to form PO4 tetrahedra that share corners with three FeO6 octahedra, a cornercorner with one PO4 tetrahedra, and a cornercorner with one LiO5 trigonal bipyramid. The corner-sharing octahedra tilt angles range from 30–49°. There are a spread of P–O bond distances ranging from 1.52–1.62 Å. In the sixth P5+ site, P5+ is bonded to four O2- atoms to form PO4 tetrahedra that share a cornercorner with one FeO6 octahedra, a cornercorner with one PO4 tetrahedra, a cornercorner with one FeO5 trigonal bipyramid, and a cornercorner with one LiO4 trigonal pyramid. The corner-sharing octahedral tilt angles are 56°. There are a spread of P–O bond distances ranging from 1.49–1.61 Å. In the seventh P5+ site, P5+ is bonded to four O2- atoms to form PO4 tetrahedra that share a cornercorner with one FeO6 octahedra, a cornercorner with one PO4 tetrahedra, a cornercorner with one LiO5 trigonal bipyramid, and a cornercorner with one FeO5 trigonal bipyramid. The corner-sharing octahedral tilt angles are 54°. There are a spread of P–O bond distances ranging from 1.47–1.63 Å. In the eighth P5+ site, P5+ is bonded to four O2- atoms to form PO4 tetrahedra that share a cornercorner with one FeO6 octahedra, a cornercorner with one PO4 tetrahedra, and a cornercorner with one FeO5 trigonal bipyramid. The corner-sharing octahedral tilt angles are 31°. There are a spread of P–O bond distances ranging from 1.48–1.63 Å. In the ninth P5+ site, P5+ is bonded to four O2- atoms to form PO4 tetrahedra that share corners with two FeO6 octahedra, a cornercorner with one LiO4 tetrahedra, a cornercorner with one PO4 tetrahedra, and a cornercorner with one LiO4 trigonal pyramid. The corner-sharing octahedra tilt angles range from 39–53°. There are a spread of P–O bond distances ranging from 1.47–1.60 Å. In the tenth P5+ site, P5+ is bonded to four O2- atoms to form PO4 tetrahedra that share corners with two FeO6 octahedra, a cornercorner with one PO4 tetrahedra, and a cornercorner with one LiO5 trigonal bipyramid. The corner-sharing octahedra tilt angles range from 58–59°. There are a spread of P–O bond distances ranging from 1.48–1.61 Å. In the eleventh P5+ site, P5+ is bonded to four O2- atoms to form PO4 tetrahedra that share a cornercorner with one FeO6 octahedra, a cornercorner with one PO4 tetrahedra, a cornercorner with one LiO4 trigonal pyramid, and an edgeedge with one FeO6 octahedra. The corner-sharing octahedral tilt angles are 56°. There are a spread of P–O bond distances ranging from 1.50–1.60 Å. In the twelfth 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 PO4 tetrahedra. The corner-sharing octahedra tilt angles range from 23–50°. There are a spread of P–O bond distances ranging from 1.51–1.62 Å. In the thirteenth 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 PO4 tetrahedra. The corner-sharing octahedra tilt angles range from 28–47°. There are a spread of P–O bond distances ranging from 1.51–1.61 Å. In the fourteenth P5+ site, P5+ is bonded to four O2- atoms to form PO4 tetrahedra that share a cornercorner with one FeO6 octahedra, a cornercorner with one LiO4 tetrahedra, a cornercorner with one PO4 tetrahedra, and a cornercorner with one FeO5 trigonal bipyramid. The corner-sharing octahedral tilt angles are 54°. There are a spread of P–O bond distances ranging from 1.49–1.60 Å. In the fifteenth P5+ site, P5+ is bonded to four O2- atoms to form PO4 tetrahedra that share a cornercorner with one FeO6 octahedra and a cornercorner with one PO4 tetrahedra. The corner-sharing octahedral tilt angles are 36°. There are a spread of P–O bond distances ranging from 1.47–1.64 Å. In the sixteenth 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 PO4 tetrahedra. The corner-sharing octahedra tilt angles range from 54–55°. There are a spread of P–O bond distances ranging from 1.49–1.60 Å. There are fifty-six inequivalent O2- sites. In the first O2- site, O2- is bonded in a distorted trigonal planar geometry to two Li1+ and one P5+ atom. In the second O2- site, O2- is bonded in a distorted bent 120 degrees geometry to one Fe3+ and one P5+ atom. In the third O2- site, O2- is bonded in a distorted trigonal planar geometry to two Fe3+ and one P5+ atom. In the fourth O2- site, O2- is bonded in a distorted bent 150 degrees geometry to two P5+ atoms. In the fifth O2- site, O2- is bonded in a distorted bent 120 degrees geometry to one Fe3+ and one P5+ atom. In the sixth O2- site, O2- is bonded in a bent 150 degrees geometry to one Fe3+ and one P5+ atom. In the seventh O2- site, O2- is bonded in a distorted trigonal planar geometry to one Li1+, one Fe3+, and one P5+ atom. In the eighth O2- site, O2- is bonded in a single-bond geometry to one P5+ atom. In the ninth O2- site, O2- is bonded in a distorted bent 120 degrees geometry to two P5+ atoms. In the tenth O2- site, O2- is bonded in a distorted bent 120 degrees geometry to one Li1+, one Fe3+, and one P5+ atom. In the eleventh O2- site, O2- is bonded in a distorted trigonal planar geometry to two Fe3+ and one P5+ atom. In the twelfth O2- site, O2- is bonded in a 3-coordinate geometry to one Li1+, one Fe3+, and one P5+ atom. In the thirteenth O2- site, O2- is bonded in a distorted trigonal non-coplanar geometry to one Li1+, one Fe3+, and one P5+ atom. In the fourteenth O2- site, O2- is bonded in a 3-coordinate geometry to one Li1+, one Fe3+, and one P5+ atom. In the fifteenth O2- site, O2- is bonded in a 3-coordinate geometry to one Li1+, one Fe3+, and one P5+ atom. In the sixteenth O2- site, O2- is bonded in a trigonal non-coplanar geometry to one Li1+, one Fe3+, and one P5+ atom. In the seventeenth O2- site, O2- is bonded in a 3-coordinate geometry to one Li1+, one Fe3+, and one P5+ atom. In the eighteenth O2- site, O2- is bonded in a distorted trigonal planar geometry to two Fe3+ and one P5+ atom. In the nineteenth O2- site, O2- is bonded in a distorted bent 120 degrees geometry to two P5+ atoms. In the twentieth O2- site, O2- is bonded in a bent 120 degrees geometry to one Li1+ and one P5+ atom. In the twenty-first O2- site, O2- is bonded in a bent 120 degrees geometry to one Li1+ and one P5+ atom. In the twenty-second O2- site, O2- is bonded in a distorted bent 120 degrees geometry to one Fe3+ and one P5+ atom. In the twenty-third O2- site, O2- is bonded in a bent 150 degrees geometry to one Fe3+ and one P5+ atom. In the twenty-fourth O2- site, O2- is bonded in a distorted bent 150 degrees geometry to two P5+ atoms. In the twenty-fifth O2- site, O2- is bonded in a distorted trigona