LiFeP2O7 crystallizes in the monoclinic Pc space group. There are two inequivalent Li sites. In the first Li site, Li(1) is bonded to one O(10), one O(2), one O(3), one O(5), and one O(7) atom to form distorted LiO5 trigonal bipyramids that share  a cornercorner with one Fe(2)O6 octahedra, corners with two equivalent Fe(1)O6 octahedra,  a cornercorner with one P(1)O4 tetrahedra, corners with two equivalent P(2)O4 tetrahedra, corners with two equivalent P(4)O4 tetrahedra, and  an edgeedge with one Fe(2)O6 octahedra. The corner-sharing octahedral tilt angles range from 56-69°. In the second Li site, Li(2) is bonded in a 4-coordinate geometry to one O(11), one O(12), one O(14), and one O(9) atom. There are two inequivalent Fe sites. In the first Fe site, Fe(1) is bonded to one O(10), one O(11), one O(12), one O(6), one O(7), and one O(8) atom to form FeO6 octahedra that share  a cornercorner with one P(2)O4 tetrahedra,  a cornercorner with one P(4)O4 tetrahedra, corners with two equivalent P(1)O4 tetrahedra, corners with two equivalent P(3)O4 tetrahedra, and corners with two equivalent Li(1)O5 trigonal bipyramids. In the second Fe site, Fe(2) is bonded to one O(14), one O(2), one O(3), one O(4), one O(5), and one O(9) atom to form FeO6 octahedra that share  a cornercorner with one P(1)O4 tetrahedra,  a cornercorner with one P(3)O4 tetrahedra, corners with two equivalent P(2)O4 tetrahedra, corners with two equivalent P(4)O4 tetrahedra,  a cornercorner with one Li(1)O5 trigonal bipyramid, and  an edgeedge with one Li(1)O5 trigonal bipyramid. There are four inequivalent P sites. In the first P site, P(1) is bonded to one O(10), one O(12), one O(13), and one O(9) atom to form PO4 tetrahedra that share  a cornercorner with one Fe(2)O6 octahedra, corners with two equivalent Fe(1)O6 octahedra,  a cornercorner with one P(3)O4 tetrahedra, and  a cornercorner with one Li(1)O5 trigonal bipyramid. The corner-sharing octahedral tilt angles range from 16-59°. In the second P site, P(2) is bonded to one O(1), one O(14), one O(5), and one O(7) atom to form PO4 tetrahedra that share  a cornercorner with one Fe(1)O6 octahedra, corners with two equivalent Fe(2)O6 octahedra,  a cornercorner with one P(4)O4 tetrahedra, and corners with two equivalent Li(1)O5 trigonal bipyramids. The corner-sharing octahedral tilt angles range from 41-49°. In the third P site, P(3) is bonded to one O(13), one O(4), one O(6), and one O(8) atom to form PO4 tetrahedra that share  a cornercorner with one Fe(2)O6 octahedra, corners with two equivalent Fe(1)O6 octahedra, and  a cornercorner with one P(1)O4 tetrahedra. The corner-sharing octahedral tilt angles range from 33-39°. In the fourth P site, P(4) is bonded to one O(1), one O(11), one O(2), and one O(3) atom to form PO4 tetrahedra that share  a cornercorner with one Fe(1)O6 octahedra, corners with two equivalent Fe(2)O6 octahedra,  a cornercorner with one P(2)O4 tetrahedra, and corners with two equivalent Li(1)O5 trigonal bipyramids. The corner-sharing octahedral tilt angles range from 27-56°. There are fourteen inequivalent O sites. In the first O site, O(1) is bonded in a bent 120 degrees geometry to one P(2) and one P(4) atom. In the second O site, O(2) is bonded in a distorted trigonal planar geometry to one Li(1), one Fe(2), and one P(4) atom. In the third O site, O(3) is bonded in a 3-coordinate geometry to one Li(1), one Fe(2), and one P(4) atom. In the fourth O site, O(4) is bonded in a bent 150 degrees geometry to one Fe(2) and one P(3) atom. In the fifth O site, O(5) is bonded in a distorted trigonal planar geometry to one Li(1), one Fe(2), and one P(2) atom. In the sixth O site, O(6) is bonded in a bent 150 degrees geometry to one Fe(1) and one P(3) atom. In the seventh O site, O(7) is bonded in a distorted trigonal planar geometry to one Li(1), one Fe(1), and one P(2) atom. In the eighth O site, O(8) is bonded in a bent 150 degrees geometry to one Fe(1) and one P(3) atom. In the ninth O site, O(9) is bonded in a distorted T-shaped geometry to one Li(2), one Fe(2), and one P(1) atom. In the tenth O site, O(10) is bonded in a 3-coordinate geometry to one Li(1), one Fe(1), and one P(1) atom. In the eleventh O site, O(11) is bonded in a distorted T-shaped geometry to one Li(2), one Fe(1), and one P(4) atom. In the twelfth O site, O(12) is bonded in a distorted trigonal non-coplanar geometry to one Li(2), one Fe(1), and one P(1) atom. In the thirteenth O site, O(13) is bonded in a bent 120 degrees geometry to one P(1) and one P(3) atom. In the fourteenth O site, O(14) is bonded in a distorted trigonal planar geometry to one Li(2), one Fe(2), and one P(2) atom.
LiFeP2O7 crystallizes in the monoclinic Pc space group. There are two inequivalent Li sites. In the first Li site, Li(1) is bonded to one O(10), one O(2), one O(3), one O(5), and one O(7) atom to form distorted LiO5 trigonal bipyramids that share  a cornercorner with one Fe(2)O6 octahedra, corners with two equivalent Fe(1)O6 octahedra,  a cornercorner with one P(1)O4 tetrahedra, corners with two equivalent P(2)O4 tetrahedra, corners with two equivalent P(4)O4 tetrahedra, and  an edgeedge with one Fe(2)O6 octahedra. The corner-sharing octahedral tilt angles range from 56-69°. The Li(1)-O(10) bond length is 2.20 Å. The Li(1)-O(2) bond length is 2.05 Å. The Li(1)-O(3) bond length is 2.37 Å. The Li(1)-O(5) bond length is 2.52 Å. The Li(1)-O(7) bond length is 2.38 Å. In the second Li site, Li(2) is bonded in a 4-coordinate geometry to one O(11), one O(12), one O(14), and one O(9) atom. The Li(2)-O(11) bond length is 1.95 Å. The Li(2)-O(12) bond length is 2.08 Å. The Li(2)-O(14) bond length is 1.97 Å. The Li(2)-O(9) bond length is 2.25 Å. There are two inequivalent Fe sites. In the first Fe site, Fe(1) is bonded to one O(10), one O(11), one O(12), one O(6), one O(7), and one O(8) atom to form FeO6 octahedra that share  a cornercorner with one P(2)O4 tetrahedra,  a cornercorner with one P(4)O4 tetrahedra, corners with two equivalent P(1)O4 tetrahedra, corners with two equivalent P(3)O4 tetrahedra, and corners with two equivalent Li(1)O5 trigonal bipyramids. The Fe(1)-O(10) bond length is 2.35 Å. The Fe(1)-O(11) bond length is 2.03 Å. The Fe(1)-O(12) bond length is 2.05 Å. The Fe(1)-O(6) bond length is 1.92 Å. The Fe(1)-O(7) bond length is 2.03 Å. The Fe(1)-O(8) bond length is 1.95 Å. In the second Fe site, Fe(2) is bonded to one O(14), one O(2), one O(3), one O(4), one O(5), and one O(9) atom to form FeO6 octahedra that share  a cornercorner with one P(1)O4 tetrahedra,  a cornercorner with one P(3)O4 tetrahedra, corners with two equivalent P(2)O4 tetrahedra, corners with two equivalent P(4)O4 tetrahedra,  a cornercorner with one Li(1)O5 trigonal bipyramid, and  an edgeedge with one Li(1)O5 trigonal bipyramid. The Fe(2)-O(14) bond length is 2.09 Å. The Fe(2)-O(2) bond length is 2.09 Å. The Fe(2)-O(3) bond length is 2.03 Å. The Fe(2)-O(4) bond length is 1.94 Å. The Fe(2)-O(5) bond length is 2.12 Å. The Fe(2)-O(9) bond length is 1.98 Å. There are four inequivalent P sites. In the first P site, P(1) is bonded to one O(10), one O(12), one O(13), and one O(9) atom to form PO4 tetrahedra that share  a cornercorner with one Fe(2)O6 octahedra, corners with two equivalent Fe(1)O6 octahedra,  a cornercorner with one P(3)O4 tetrahedra, and  a cornercorner with one Li(1)O5 trigonal bipyramid. The corner-sharing octahedral tilt angles range from 16-59°. The P(1)-O(10) bond length is 1.53 Å. The P(1)-O(12) bond length is 1.54 Å. The P(1)-O(13) bond length is 1.62 Å. The P(1)-O(9) bond length is 1.53 Å. In the second P site, P(2) is bonded to one O(1), one O(14), one O(5), and one O(7) atom to form PO4 tetrahedra that share  a cornercorner with one Fe(1)O6 octahedra, corners with two equivalent Fe(2)O6 octahedra,  a cornercorner with one P(4)O4 tetrahedra, and corners with two equivalent Li(1)O5 trigonal bipyramids. The corner-sharing octahedral tilt angles range from 41-49°. The P(2)-O(1) bond length is 1.63 Å. The P(2)-O(14) bond length is 1.53 Å. The P(2)-O(5) bond length is 1.53 Å. The P(2)-O(7) bond length is 1.54 Å. In the third P site, P(3) is bonded to one O(13), one O(4), one O(6), and one O(8) atom to form PO4 tetrahedra that share  a cornercorner with one Fe(2)O6 octahedra, corners with two equivalent Fe(1)O6 octahedra, and  a cornercorner with one P(1)O4 tetrahedra. The corner-sharing octahedral tilt angles range from 33-39°. The P(3)-O(13) bond length is 1.62 Å. The P(3)-O(4) bond length is 1.52 Å. The P(3)-O(6) bond length is 1.53 Å. The P(3)-O(8) bond length is 1.52 Å. In the fourth P site, P(4) is bonded to one O(1), one O(11), one O(2), and one O(3) atom to form PO4 tetrahedra that share  a cornercorner with one Fe(1)O6 octahedra, corners with two equivalent Fe(2)O6 octahedra,  a cornercorner with one P(2)O4 tetrahedra, and corners with two equivalent Li(1)O5 trigonal bipyramids. The corner-sharing octahedral tilt angles range from 27-56°. The P(4)-O(1) bond length is 1.62 Å. The P(4)-O(11) bond length is 1.53 Å. The P(4)-O(2) bond length is 1.53 Å. The P(4)-O(3) bond length is 1.54 Å. There are fourteen inequivalent O sites. In the first O site, O(1) is bonded in a bent 120 degrees geometry to one P(2) and one P(4) atom. In the second O site, O(2) is bonded in a distorted trigonal planar geometry to one Li(1), one Fe(2), and one P(4) atom. In the third O site, O(3) is bonded in a 3-coordinate geometry to one Li(1), one Fe(2), and one P(4) atom. In the fourth O site, O(4) is bonded in a bent 150 degrees geometry to one Fe(2) and one P(3) atom. In the fifth O site, O(5) is bonded in a distorted trigonal planar geometry to one Li(1), one Fe(2), and one P(2) atom. In the sixth O site, O(6) is bonded in a bent 150 degrees geometry to one Fe(1) and one P(3) atom. In the seventh O site, O(7) is bonded in a distorted trigonal planar geometry to one Li(1), one Fe(1), and one P(2) atom. In the eighth O site, O(8) is bonded in a bent 150 degrees geometry to one Fe(1) and one P(3) atom. In the ninth O site, O(9) is bonded in a distorted T-shaped geometry to one Li(2), one Fe(2), and one P(1) atom. In the tenth O site, O(10) is bonded in a 3-coordinate geometry to one Li(1), one Fe(1), and one P(1) atom. In the eleventh O site, O(11) is bonded in a distorted T-shaped geometry to one Li(2), one Fe(1), and one P(4) atom. In the twelfth O site, O(12) is bonded in a distorted trigonal non-coplanar geometry to one Li(2), one Fe(1), and one P(1) atom. In the thirteenth O site, O(13) is bonded in a bent 120 degrees geometry to one P(1) and one P(3) atom. In the fourteenth O site, O(14) is bonded in a distorted trigonal planar geometry to one Li(2), one Fe(2), and one P(2) atom.