Li2Fe2P2O9F crystallizes in the triclinic P1 space group. There are two inequivalent Li sites. In the first Li site, Li(1) is bonded to one O(1), one O(3), one O(4), one O(5), and one O(9) atom to form distorted LiO5 square pyramids that share corners with two equivalent Fe(2)O5F octahedra,  a cornercorner with one P(1)O4 tetrahedra,  a cornercorner with one P(2)O4 tetrahedra, edges with two equivalent Fe(1)O5F octahedra,  an edgeedge with one Li(2)O4F square pyramid, and  an edgeedge with one P(1)O4 tetrahedra. The corner-sharing octahedral tilt angles range from 48-66°. In the second Li site, Li(2) is bonded to one O(2), one O(3), one O(4), one O(6), and one F(1) atom to form distorted LiO4F square pyramids that share corners with two equivalent Fe(2)O5F octahedra,  a cornercorner with one P(1)O4 tetrahedra,  a cornercorner with one P(2)O4 tetrahedra, edges with two equivalent Fe(1)O5F octahedra,  an edgeedge with one Li(1)O5 square pyramid, and  an edgeedge with one P(2)O4 tetrahedra. The corner-sharing octahedral tilt angles range from 50-64°. There are two inequivalent Fe sites. In the first Fe site, Fe(1) is bonded to one O(1), one O(2), one O(3), one O(4), one O(9), and one F(1) atom to form FeO5F octahedra that share corners with two equivalent Fe(2)O5F octahedra, corners with two equivalent P(1)O4 tetrahedra, corners with two equivalent P(2)O4 tetrahedra, edges with two equivalent Li(2)O4F square pyramids, and edges with two equivalent Li(1)O5 square pyramids. The corner-sharing octahedral tilt angles are 44°. In the second Fe site, Fe(2) is bonded to one O(5), one O(6), one O(7), one O(8), one O(9), and one F(1) atom to form FeO5F octahedra that share corners with two equivalent Fe(1)O5F octahedra, corners with two equivalent Li(2)O4F square pyramids, corners with two equivalent Li(1)O5 square pyramids, corners with two equivalent P(1)O4 tetrahedra, and corners with two equivalent P(2)O4 tetrahedra. The corner-sharing octahedral tilt angles are 44°. There are two inequivalent P sites. In the first P site, P(1) is bonded to one O(1), one O(3), one O(5), and one O(7) atom to form PO4 tetrahedra that share corners with two equivalent Fe(1)O5F octahedra, corners with two equivalent Fe(2)O5F octahedra,  a cornercorner with one Li(2)O4F square pyramid,  a cornercorner with one Li(1)O5 square pyramid, and  an edgeedge with one Li(1)O5 square pyramid. The corner-sharing octahedral tilt angles range from 22-54°. In the second P site, P(2) is bonded to one O(2), one O(4), one O(6), and one O(8) atom to form PO4 tetrahedra that share corners with two equivalent Fe(1)O5F octahedra, corners with two equivalent Fe(2)O5F octahedra,  a cornercorner with one Li(2)O4F square pyramid,  a cornercorner with one Li(1)O5 square pyramid, and  an edgeedge with one Li(2)O4F square pyramid. The corner-sharing octahedral tilt angles range from 27-52°. There are nine inequivalent O sites. In the first O site, O(1) is bonded in a T-shaped geometry to one Li(1), one Fe(1), and one P(1) atom. In the second O site, O(2) is bonded in a T-shaped geometry to one Li(2), one Fe(1), and one P(2) atom. In the third O site, O(3) is bonded in a rectangular see-saw-like geometry to one Li(1), one Li(2), one Fe(1), and one P(1) atom. In the fourth O site, O(4) is bonded in a rectangular see-saw-like geometry to one Li(1), one Li(2), one Fe(1), and one P(2) atom. In the fifth O site, O(5) is bonded in a 3-coordinate geometry to one Li(1), one Fe(2), and one P(1) atom. In the sixth O site, O(6) is bonded in a distorted trigonal planar geometry to one Li(2), one Fe(2), and one P(2) atom. In the seventh O site, O(7) is bonded in a distorted bent 150 degrees geometry to one Fe(2) and one P(1) atom. In the eighth O site, O(8) is bonded in a bent 150 degrees geometry to one Fe(2) and one P(2) atom. In the ninth O site, O(9) is bonded in a distorted trigonal non-coplanar geometry to one Li(1), one Fe(1), and one Fe(2) atom. F(1) is bonded in a distorted trigonal planar geometry to one Li(2), one Fe(1), and one Fe(2) atom.
Li2Fe2P2O9F crystallizes in the triclinic P1 space group. There are two inequivalent Li sites. In the first Li site, Li(1) is bonded to one O(1), one O(3), one O(4), one O(5), and one O(9) atom to form distorted LiO5 square pyramids that share corners with two equivalent Fe(2)O5F octahedra,  a cornercorner with one P(1)O4 tetrahedra,  a cornercorner with one P(2)O4 tetrahedra, edges with two equivalent Fe(1)O5F octahedra,  an edgeedge with one Li(2)O4F square pyramid, and  an edgeedge with one P(1)O4 tetrahedra. The corner-sharing octahedral tilt angles range from 48-66°. The Li(1)-O(1) bond length is 2.15 Å. The Li(1)-O(3) bond length is 2.18 Å. The Li(1)-O(4) bond length is 2.32 Å. The Li(1)-O(5) bond length is 2.11 Å. The Li(1)-O(9) bond length is 1.98 Å. In the second Li site, Li(2) is bonded to one O(2), one O(3), one O(4), one O(6), and one F(1) atom to form distorted LiO4F square pyramids that share corners with two equivalent Fe(2)O5F octahedra,  a cornercorner with one P(1)O4 tetrahedra,  a cornercorner with one P(2)O4 tetrahedra, edges with two equivalent Fe(1)O5F octahedra,  an edgeedge with one Li(1)O5 square pyramid, and  an edgeedge with one P(2)O4 tetrahedra. The corner-sharing octahedral tilt angles range from 50-64°. The Li(2)-O(2) bond length is 2.17 Å. The Li(2)-O(3) bond length is 2.26 Å. The Li(2)-O(4) bond length is 2.13 Å. The Li(2)-O(6) bond length is 2.07 Å. The Li(2)-F(1) bond length is 1.95 Å. There are two inequivalent Fe sites. In the first Fe site, Fe(1) is bonded to one O(1), one O(2), one O(3), one O(4), one O(9), and one F(1) atom to form FeO5F octahedra that share corners with two equivalent Fe(2)O5F octahedra, corners with two equivalent P(1)O4 tetrahedra, corners with two equivalent P(2)O4 tetrahedra, edges with two equivalent Li(2)O4F square pyramids, and edges with two equivalent Li(1)O5 square pyramids. The corner-sharing octahedral tilt angles are 44°. The Fe(1)-O(1) bond length is 2.00 Å. The Fe(1)-O(2) bond length is 1.95 Å. The Fe(1)-O(3) bond length is 2.08 Å. The Fe(1)-O(4) bond length is 2.07 Å. The Fe(1)-O(9) bond length is 1.92 Å. The Fe(1)-F(1) bond length is 2.01 Å. In the second Fe site, Fe(2) is bonded to one O(5), one O(6), one O(7), one O(8), one O(9), and one F(1) atom to form FeO5F octahedra that share corners with two equivalent Fe(1)O5F octahedra, corners with two equivalent Li(2)O4F square pyramids, corners with two equivalent Li(1)O5 square pyramids, corners with two equivalent P(1)O4 tetrahedra, and corners with two equivalent P(2)O4 tetrahedra. The corner-sharing octahedral tilt angles are 44°. The Fe(2)-O(5) bond length is 2.05 Å. The Fe(2)-O(6) bond length is 2.02 Å. The Fe(2)-O(7) bond length is 2.01 Å. The Fe(2)-O(8) bond length is 2.00 Å. The Fe(2)-O(9) bond length is 1.91 Å. The Fe(2)-F(1) bond length is 2.02 Å. There are two inequivalent P sites. In the first P site, P(1) is bonded to one O(1), one O(3), one O(5), and one O(7) atom to form PO4 tetrahedra that share corners with two equivalent Fe(1)O5F octahedra, corners with two equivalent Fe(2)O5F octahedra,  a cornercorner with one Li(2)O4F square pyramid,  a cornercorner with one Li(1)O5 square pyramid, and  an edgeedge with one Li(1)O5 square pyramid. The corner-sharing octahedral tilt angles range from 22-54°. The P(1)-O(1) bond length is 1.56 Å. The P(1)-O(3) bond length is 1.56 Å. The P(1)-O(5) bond length is 1.56 Å. The P(1)-O(7) bond length is 1.53 Å. In the second P site, P(2) is bonded to one O(2), one O(4), one O(6), and one O(8) atom to form PO4 tetrahedra that share corners with two equivalent Fe(1)O5F octahedra, corners with two equivalent Fe(2)O5F octahedra,  a cornercorner with one Li(2)O4F square pyramid,  a cornercorner with one Li(1)O5 square pyramid, and  an edgeedge with one Li(2)O4F square pyramid. The corner-sharing octahedral tilt angles range from 27-52°. The P(2)-O(2) bond length is 1.56 Å. The P(2)-O(4) bond length is 1.56 Å. The P(2)-O(6) bond length is 1.55 Å. The P(2)-O(8) bond length is 1.54 Å. There are nine inequivalent O sites. In the first O site, O(1) is bonded in a T-shaped geometry to one Li(1), one Fe(1), and one P(1) atom. In the second O site, O(2) is bonded in a T-shaped geometry to one Li(2), one Fe(1), and one P(2) atom. In the third O site, O(3) is bonded in a rectangular see-saw-like geometry to one Li(1), one Li(2), one Fe(1), and one P(1) atom. In the fourth O site, O(4) is bonded in a rectangular see-saw-like geometry to one Li(1), one Li(2), one Fe(1), and one P(2) atom. In the fifth O site, O(5) is bonded in a 3-coordinate geometry to one Li(1), one Fe(2), and one P(1) atom. In the sixth O site, O(6) is bonded in a distorted trigonal planar geometry to one Li(2), one Fe(2), and one P(2) atom. In the seventh O site, O(7) is bonded in a distorted bent 150 degrees geometry to one Fe(2) and one P(1) atom. In the eighth O site, O(8) is bonded in a bent 150 degrees geometry to one Fe(2) and one P(2) atom. In the ninth O site, O(9) is bonded in a distorted trigonal non-coplanar geometry to one Li(1), one Fe(1), and one Fe(2) atom. F(1) is bonded in a distorted trigonal planar geometry to one Li(2), one Fe(1), and one Fe(2) atom.