LiFe2Si2O7 crystallizes in the monoclinic P2_1/c space group. Li(1) is bonded in a distorted trigonal non-coplanar geometry to one O(1), one O(3), and one O(6) atom. There are two inequivalent Fe sites. In the first Fe site, Fe(1) is bonded in a 5-coordinate geometry to one O(1), one O(2), one O(4), one O(6), and one O(7) atom. In the second Fe site, Fe(2) is bonded to one O(3), one O(4), one O(5), and one O(7) atom to form FeO4 tetrahedra that share corners with two equivalent Si(1)O4 tetrahedra and corners with two equivalent Si(2)O4 tetrahedra. There are two inequivalent Si sites. In the first Si site, Si(1) is bonded to one O(1), one O(2), one O(4), and one O(7) atom to form SiO4 tetrahedra that share  a cornercorner with one Si(2)O4 tetrahedra and corners with two equivalent Fe(2)O4 tetrahedra. In the second Si site, Si(2) is bonded to one O(2), one O(3), one O(5), and one O(6) atom to form SiO4 tetrahedra that share  a cornercorner with one Si(1)O4 tetrahedra and corners with two equivalent Fe(2)O4 tetrahedra. There are seven inequivalent O sites. In the first O site, O(1) is bonded in a trigonal planar geometry to one Li(1), one Fe(1), and one Si(1) atom. In the second O site, O(2) is bonded in a distorted bent 120 degrees geometry to one Fe(1), one Si(1), and one Si(2) atom. In the third O site, O(3) is bonded in a trigonal planar geometry to one Li(1), one Fe(2), and one Si(2) atom. In the fourth O site, O(4) is bonded in a distorted trigonal planar geometry to one Fe(1), one Fe(2), and one Si(1) atom. In the fifth O site, O(5) is bonded in a bent 120 degrees geometry to one Fe(2) and one Si(2) atom. In the sixth O site, O(6) is bonded in a trigonal planar geometry to one Li(1), one Fe(1), and one Si(2) atom. In the seventh O site, O(7) is bonded in a trigonal non-coplanar geometry to one Fe(1), one Fe(2), and one Si(1) atom.
LiFe2Si2O7 crystallizes in the monoclinic P2_1/c space group. Li(1) is bonded in a distorted trigonal non-coplanar geometry to one O(1), one O(3), and one O(6) atom. The Li(1)-O(1) bond length is 1.96 Å. The Li(1)-O(3) bond length is 2.02 Å. The Li(1)-O(6) bond length is 1.92 Å. There are two inequivalent Fe sites. In the first Fe site, Fe(1) is bonded in a 5-coordinate geometry to one O(1), one O(2), one O(4), one O(6), and one O(7) atom. The Fe(1)-O(1) bond length is 2.01 Å. The Fe(1)-O(2) bond length is 2.48 Å. The Fe(1)-O(4) bond length is 2.15 Å. The Fe(1)-O(6) bond length is 2.00 Å. The Fe(1)-O(7) bond length is 2.16 Å. In the second Fe site, Fe(2) is bonded to one O(3), one O(4), one O(5), and one O(7) atom to form FeO4 tetrahedra that share corners with two equivalent Si(1)O4 tetrahedra and corners with two equivalent Si(2)O4 tetrahedra. The Fe(2)-O(3) bond length is 1.90 Å. The Fe(2)-O(4) bond length is 1.95 Å. The Fe(2)-O(5) bond length is 1.85 Å. The Fe(2)-O(7) bond length is 1.93 Å. There are two inequivalent Si sites. In the first Si site, Si(1) is bonded to one O(1), one O(2), one O(4), and one O(7) atom to form SiO4 tetrahedra that share  a cornercorner with one Si(2)O4 tetrahedra and corners with two equivalent Fe(2)O4 tetrahedra. The Si(1)-O(1) bond length is 1.61 Å. The Si(1)-O(2) bond length is 1.67 Å. The Si(1)-O(4) bond length is 1.67 Å. The Si(1)-O(7) bond length is 1.65 Å. In the second Si site, Si(2) is bonded to one O(2), one O(3), one O(5), and one O(6) atom to form SiO4 tetrahedra that share  a cornercorner with one Si(1)O4 tetrahedra and corners with two equivalent Fe(2)O4 tetrahedra. The Si(2)-O(2) bond length is 1.69 Å. The Si(2)-O(3) bond length is 1.64 Å. The Si(2)-O(5) bond length is 1.63 Å. The Si(2)-O(6) bond length is 1.62 Å. There are seven inequivalent O sites. In the first O site, O(1) is bonded in a trigonal planar geometry to one Li(1), one Fe(1), and one Si(1) atom. In the second O site, O(2) is bonded in a distorted bent 120 degrees geometry to one Fe(1), one Si(1), and one Si(2) atom. In the third O site, O(3) is bonded in a trigonal planar geometry to one Li(1), one Fe(2), and one Si(2) atom. In the fourth O site, O(4) is bonded in a distorted trigonal planar geometry to one Fe(1), one Fe(2), and one Si(1) atom. In the fifth O site, O(5) is bonded in a bent 120 degrees geometry to one Fe(2) and one Si(2) atom. In the sixth O site, O(6) is bonded in a trigonal planar geometry to one Li(1), one Fe(1), and one Si(2) atom. In the seventh O site, O(7) is bonded in a trigonal non-coplanar geometry to one Fe(1), one Fe(2), and one Si(1) atom.