LiFeP2O7 crystallizes in the triclinic P-1 space group. Li(1) is bonded to one O(1), one O(4), one O(6), and two equivalent O(5) atoms to form distorted LiO5 trigonal bipyramids that share corners with two equivalent P(2)O4 tetrahedra, corners with three equivalent P(1)O4 tetrahedra, and  an edgeedge with one Li(1)O5 trigonal bipyramid. Fe(1) is bonded in a 6-coordinate geometry to one O(1), one O(5), one O(6), one O(7), and two equivalent O(2) atoms. There are two inequivalent P sites. In the first P site, P(1) is bonded to one O(1), one O(2), one O(3), and one O(5) atom to form PO4 tetrahedra that share  a cornercorner with one P(2)O4 tetrahedra and corners with three equivalent Li(1)O5 trigonal bipyramids. In the second P site, P(2) is bonded to one O(3), one O(4), one O(6), and one O(7) atom to form PO4 tetrahedra that share  a cornercorner with one P(1)O4 tetrahedra and corners with two equivalent Li(1)O5 trigonal bipyramids. There are seven inequivalent O sites. In the first O site, O(1) is bonded in a distorted trigonal planar geometry to one Li(1), one Fe(1), and one P(1) atom. In the second O site, O(2) is bonded in a 2-coordinate geometry to two equivalent Fe(1) and one P(1) atom. In the third O site, O(3) is bonded in a bent 120 degrees geometry to one P(1) and one P(2) atom. In the fourth O site, O(4) is bonded in a bent 150 degrees geometry to one Li(1) and one P(2) atom. In the fifth O site, O(5) is bonded in a 4-coordinate geometry to two equivalent Li(1), one Fe(1), and one P(1) atom. In the sixth O site, O(6) is bonded in a distorted trigonal planar geometry to one Li(1), one Fe(1), and one P(2) atom. In the seventh O site, O(7) is bonded in a bent 120 degrees geometry to one Fe(1) and one P(2) atom.
LiFeP2O7 crystallizes in the triclinic P-1 space group. Li(1) is bonded to one O(1), one O(4), one O(6), and two equivalent O(5) atoms to form distorted LiO5 trigonal bipyramids that share corners with two equivalent P(2)O4 tetrahedra, corners with three equivalent P(1)O4 tetrahedra, and  an edgeedge with one Li(1)O5 trigonal bipyramid. The Li(1)-O(1) bond length is 2.31 Å. The Li(1)-O(4) bond length is 1.90 Å. The Li(1)-O(6) bond length is 2.16 Å. There is one shorter (2.08 Å) and one longer (2.11 Å) Li(1)-O(5) bond length. Fe(1) is bonded in a 6-coordinate geometry to one O(1), one O(5), one O(6), one O(7), and two equivalent O(2) atoms. The Fe(1)-O(1) bond length is 2.05 Å. The Fe(1)-O(5) bond length is 2.32 Å. The Fe(1)-O(6) bond length is 1.99 Å. The Fe(1)-O(7) bond length is 1.91 Å. There is one shorter (2.03 Å) and one longer (2.58 Å) Fe(1)-O(2) bond length. There are two inequivalent P sites. In the first P site, P(1) is bonded to one O(1), one O(2), one O(3), and one O(5) atom to form PO4 tetrahedra that share  a cornercorner with one P(2)O4 tetrahedra and corners with three equivalent Li(1)O5 trigonal bipyramids. The P(1)-O(1) bond length is 1.56 Å. The P(1)-O(2) bond length is 1.55 Å. The P(1)-O(3) bond length is 1.59 Å. The P(1)-O(5) bond length is 1.53 Å. In the second P site, P(2) is bonded to one O(3), one O(4), one O(6), and one O(7) atom to form PO4 tetrahedra that share  a cornercorner with one P(1)O4 tetrahedra and corners with two equivalent Li(1)O5 trigonal bipyramids. The P(2)-O(3) bond length is 1.64 Å. The P(2)-O(4) bond length is 1.49 Å. The P(2)-O(6) bond length is 1.55 Å. The P(2)-O(7) bond length is 1.56 Å. There are seven inequivalent O sites. In the first O site, O(1) is bonded in a distorted trigonal planar geometry to one Li(1), one Fe(1), and one P(1) atom. In the second O site, O(2) is bonded in a 2-coordinate geometry to two equivalent Fe(1) and one P(1) atom. In the third O site, O(3) is bonded in a bent 120 degrees geometry to one P(1) and one P(2) atom. In the fourth O site, O(4) is bonded in a bent 150 degrees geometry to one Li(1) and one P(2) atom. In the fifth O site, O(5) is bonded in a 4-coordinate geometry to two equivalent Li(1), one Fe(1), and one P(1) atom. In the sixth O site, O(6) is bonded in a distorted trigonal planar geometry to one Li(1), one Fe(1), and one P(2) atom. In the seventh O site, O(7) is bonded in a bent 120 degrees geometry to one Fe(1) and one P(2) atom.