Li5Fe(P2O7)2 crystallizes in the triclinic P-1 space group. There are five inequivalent Li sites. In the first Li site, Li(1) is bonded to one O(2), one O(4), one O(6), one O(8), and one O(9) atom to form LiO5 trigonal bipyramids that share  a cornercorner with one P(1)O4 tetrahedra,  a cornercorner with one P(3)O4 tetrahedra,  a cornercorner with one P(4)O4 tetrahedra, corners with two equivalent P(2)O4 tetrahedra, and  an edgeedge with one Fe(1)O6 octahedra. In the second Li site, Li(2) is bonded in a 3-coordinate geometry to one O(1), one O(12), one O(14), and one O(6) atom. In the third Li site, Li(3) is bonded in a 6-coordinate geometry to one O(10), one O(13), one O(2), one O(3), one O(5), and one O(9) atom. In the fourth Li site, Li(4) is bonded in a distorted rectangular see-saw-like geometry to one O(5), one O(8), and two equivalent O(13) atoms. In the fifth Li site, Li(5) is bonded in a 5-coordinate geometry to one O(11), one O(12), one O(6), and two equivalent O(14) atoms. Fe(1) is bonded to one O(1), one O(11), one O(12), one O(2), one O(4), and one O(5) atom to form distorted FeO6 octahedra that share  a cornercorner with one P(3)O4 tetrahedra,  a cornercorner with one P(4)O4 tetrahedra, corners with two equivalent P(1)O4 tetrahedra, corners with two equivalent P(2)O4 tetrahedra, 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(2), one O(3), one O(5), and one O(7) atom to form PO4 tetrahedra that share 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 61-74°. In the second P site, P(2) is bonded to one O(1), one O(10), one O(4), and one O(6) atom to form PO4 tetrahedra that share corners with two equivalent Fe(1)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 44-45°. In the third P site, P(3) is bonded to one O(11), one O(13), one O(7), and one O(9) atom to form PO4 tetrahedra that share  a cornercorner with one Fe(1)O6 octahedra,  a cornercorner with one P(1)O4 tetrahedra, and  a cornercorner with one Li(1)O5 trigonal bipyramid. The corner-sharing octahedral tilt angles are 47°. In the fourth P site, P(4) is bonded to one O(10), one O(12), one O(14), and one O(8) atom to form PO4 tetrahedra that share  a cornercorner with one Fe(1)O6 octahedra,  a cornercorner with one P(2)O4 tetrahedra, and  a cornercorner with one Li(1)O5 trigonal bipyramid. The corner-sharing octahedral tilt angles are 41°. There are fourteen inequivalent O sites. In the first O site, O(1) is bonded in a distorted trigonal planar geometry to one Li(2), one Fe(1), and one P(2) atom. In the second O site, O(2) is bonded to one Li(1), one Li(3), one Fe(1), and one P(1) atom to form distorted OLi2FeP tetrahedra that share  a cornercorner with one O(5)Li2FeP trigonal pyramid,  a cornercorner with one O(13)Li3P trigonal pyramid, and  an edgeedge with one O(5)Li2FeP trigonal pyramid. In the third O site, O(3) is bonded in a distorted linear geometry to one Li(3) and one P(1) atom. In the fourth O site, O(4) is bonded in a distorted trigonal planar geometry to one Li(1), one Fe(1), and one P(2) atom. In the fifth O site, O(5) is bonded to one Li(3), one Li(4), one Fe(1), and one P(1) atom to form distorted OLi2FeP trigonal pyramids that share  a cornercorner with one O(2)Li2FeP tetrahedra,  a cornercorner with one O(13)Li3P trigonal pyramid,  an edgeedge with one O(2)Li2FeP tetrahedra, and  an edgeedge with one O(13)Li3P trigonal pyramid. In the sixth O site, O(6) is bonded in a 4-coordinate geometry to one Li(1), one Li(2), one Li(5), and one P(2) atom. In the seventh O site, O(7) is bonded in a bent 120 degrees geometry to one P(1) and one P(3) atom. In the eighth O site, O(8) is bonded in a 3-coordinate geometry to one Li(1), one Li(4), and one P(4) atom. In the ninth O site, O(9) is bonded in a distorted trigonal non-coplanar geometry to one Li(1), one Li(3), and one P(3) atom. In the tenth O site, O(10) is bonded in a 3-coordinate geometry to one Li(3), one P(2), and one P(4) atom. In the eleventh O site, O(11) is bonded in a distorted trigonal planar geometry to one Li(5), one Fe(1), and one P(3) atom. In the twelfth O site, O(12) is bonded in a 4-coordinate geometry to one Li(2), one Li(5), one Fe(1), and one P(4) atom. In the thirteenth O site, O(13) is bonded to one Li(3), two equivalent Li(4), and one P(3) atom to form OLi3P trigonal pyramids that share  a cornercorner with one O(2)Li2FeP tetrahedra,  a cornercorner with one O(5)Li2FeP trigonal pyramid,  an edgeedge with one O(5)Li2FeP trigonal pyramid, and  an edgeedge with one O(13)Li3P trigonal pyramid. In the fourteenth O site, O(14) is bonded to one Li(2), two equivalent Li(5), and one P(4) atom to form edge-sharing OLi3P trigonal pyramids.
Li5Fe(P2O7)2 crystallizes in the triclinic P-1 space group. There are five inequivalent Li sites. In the first Li site, Li(1) is bonded to one O(2), one O(4), one O(6), one O(8), and one O(9) atom to form LiO5 trigonal bipyramids that share  a cornercorner with one P(1)O4 tetrahedra,  a cornercorner with one P(3)O4 tetrahedra,  a cornercorner with one P(4)O4 tetrahedra, corners with two equivalent P(2)O4 tetrahedra, and  an edgeedge with one Fe(1)O6 octahedra. The Li(1)-O(2) bond length is 2.21 Å. The Li(1)-O(4) bond length is 2.27 Å. The Li(1)-O(6) bond length is 2.02 Å. The Li(1)-O(8) bond length is 2.04 Å. The Li(1)-O(9) bond length is 2.04 Å. In the second Li site, Li(2) is bonded in a 3-coordinate geometry to one O(1), one O(12), one O(14), and one O(6) atom. The Li(2)-O(1) bond length is 2.01 Å. The Li(2)-O(12) bond length is 2.54 Å. The Li(2)-O(14) bond length is 2.00 Å. The Li(2)-O(6) bond length is 1.95 Å. In the third Li site, Li(3) is bonded in a 6-coordinate geometry to one O(10), one O(13), one O(2), one O(3), one O(5), and one O(9) atom. The Li(3)-O(10) bond length is 2.51 Å. The Li(3)-O(13) bond length is 2.12 Å. The Li(3)-O(2) bond length is 2.46 Å. The Li(3)-O(3) bond length is 1.91 Å. The Li(3)-O(5) bond length is 2.44 Å. The Li(3)-O(9) bond length is 2.11 Å. In the fourth Li site, Li(4) is bonded in a distorted rectangular see-saw-like geometry to one O(5), one O(8), and two equivalent O(13) atoms. The Li(4)-O(5) bond length is 2.04 Å. The Li(4)-O(8) bond length is 2.04 Å. There is one shorter (2.07 Å) and one longer (2.18 Å) Li(4)-O(13) bond length. In the fifth Li site, Li(5) is bonded in a 5-coordinate geometry to one O(11), one O(12), one O(6), and two equivalent O(14) atoms. The Li(5)-O(11) bond length is 2.03 Å. The Li(5)-O(12) bond length is 2.18 Å. The Li(5)-O(6) bond length is 2.53 Å. There is one shorter (2.25 Å) and one longer (2.26 Å) Li(5)-O(14) bond length. Fe(1) is bonded to one O(1), one O(11), one O(12), one O(2), one O(4), and one O(5) atom to form distorted FeO6 octahedra that share  a cornercorner with one P(3)O4 tetrahedra,  a cornercorner with one P(4)O4 tetrahedra, corners with two equivalent P(1)O4 tetrahedra, corners with two equivalent P(2)O4 tetrahedra, and  an edgeedge with one Li(1)O5 trigonal bipyramid. The Fe(1)-O(1) bond length is 2.24 Å. The Fe(1)-O(11) bond length is 2.15 Å. The Fe(1)-O(12) bond length is 1.99 Å. The Fe(1)-O(2) bond length is 2.21 Å. The Fe(1)-O(4) bond length is 2.01 Å. The Fe(1)-O(5) bond length is 2.07 Å. There are four inequivalent P sites. In the first P site, P(1) is bonded to one O(2), one O(3), one O(5), and one O(7) atom to form PO4 tetrahedra that share 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 61-74°. The P(1)-O(2) bond length is 1.55 Å. The P(1)-O(3) bond length is 1.49 Å. The P(1)-O(5) bond length is 1.57 Å. The P(1)-O(7) bond length is 1.61 Å. In the second P site, P(2) is bonded to one O(1), one O(10), one O(4), and one O(6) atom to form PO4 tetrahedra that share corners with two equivalent Fe(1)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 44-45°. The P(2)-O(1) bond length is 1.53 Å. The P(2)-O(10) bond length is 1.62 Å. The P(2)-O(4) bond length is 1.55 Å. The P(2)-O(6) bond length is 1.52 Å. In the third P site, P(3) is bonded to one O(11), one O(13), one O(7), and one O(9) atom to form PO4 tetrahedra that share  a cornercorner with one Fe(1)O6 octahedra,  a cornercorner with one P(1)O4 tetrahedra, and  a cornercorner with one Li(1)O5 trigonal bipyramid. The corner-sharing octahedral tilt angles are 47°. The P(3)-O(11) bond length is 1.54 Å. The P(3)-O(13) bond length is 1.54 Å. The P(3)-O(7) bond length is 1.64 Å. The P(3)-O(9) bond length is 1.53 Å. In the fourth P site, P(4) is bonded to one O(10), one O(12), one O(14), and one O(8) atom to form PO4 tetrahedra that share  a cornercorner with one Fe(1)O6 octahedra,  a cornercorner with one P(2)O4 tetrahedra, and  a cornercorner with one Li(1)O5 trigonal bipyramid. The corner-sharing octahedral tilt angles are 41°. The P(4)-O(10) bond length is 1.62 Å. The P(4)-O(12) bond length is 1.55 Å. The P(4)-O(14) bond length is 1.53 Å. The P(4)-O(8) bond length is 1.52 Å. There are fourteen inequivalent O sites. In the first O site, O(1) is bonded in a distorted trigonal planar geometry to one Li(2), one Fe(1), and one P(2) atom. In the second O site, O(2) is bonded to one Li(1), one Li(3), one Fe(1), and one P(1) atom to form distorted OLi2FeP tetrahedra that share  a cornercorner with one O(5)Li2FeP trigonal pyramid,  a cornercorner with one O(13)Li3P trigonal pyramid, and  an edgeedge with one O(5)Li2FeP trigonal pyramid. In the third O site, O(3) is bonded in a distorted linear geometry to one Li(3) and one P(1) atom. In the fourth O site, O(4) is bonded in a distorted trigonal planar geometry to one Li(1), one Fe(1), and one P(2) atom. In the fifth O site, O(5) is bonded to one Li(3), one Li(4), one Fe(1), and one P(1) atom to form distorted OLi2FeP trigonal pyramids that share  a cornercorner with one O(2)Li2FeP tetrahedra,  a cornercorner with one O(13)Li3P trigonal pyramid,  an edgeedge with one O(2)Li2FeP tetrahedra, and  an edgeedge with one O(13)Li3P trigonal pyramid. In the sixth O site, O(6) is bonded in a 4-coordinate geometry to one Li(1), one Li(2), one Li(5), and one P(2) atom. In the seventh O site, O(7) is bonded in a bent 120 degrees geometry to one P(1) and one P(3) atom. In the eighth O site, O(8) is bonded in a 3-coordinate geometry to one Li(1), one Li(4), and one P(4) atom. In the ninth O site, O(9) is bonded in a distorted trigonal non-coplanar geometry to one Li(1), one Li(3), and one P(3) atom. In the tenth O site, O(10) is bonded in a 3-coordinate geometry to one Li(3), one P(2), and one P(4) atom. In the eleventh O site, O(11) is bonded in a distorted trigonal planar geometry to one Li(5), one Fe(1), and one P(3) atom. In the twelfth O site, O(12) is bonded in a 4-coordinate geometry to one Li(2), one Li(5), one Fe(1), and one P(4) atom. In the thirteenth O site, O(13) is bonded to one Li(3), two equivalent Li(4), and one P(3) atom to form OLi3P trigonal pyramids that share  a cornercorner with one O(2)Li2FeP tetrahedra,  a cornercorner with one O(5)Li2FeP trigonal pyramid,  an edgeedge with one O(5)Li2FeP trigonal pyramid, and  an edgeedge with one O(13)Li3P trigonal pyramid. In the fourteenth O site, O(14) is bonded to one Li(2), two equivalent Li(5), and one P(4) atom to form edge-sharing OLi3P trigonal pyramids.