Li2FeSi3O8 crystallizes in the triclinic P1 space group. There are two inequivalent Li sites. In the first Li site, Li(1) is bonded in a distorted see-saw-like geometry to one O(2), one O(3), one O(4), and one O(7) atom. In the second Li site, Li(2) is bonded to one O(1), one O(3), one O(5), and one O(8) atom to form distorted LiO4 trigonal pyramids that share  a cornercorner with one Si(2)O4 tetrahedra, corners with two equivalent Si(1)O4 tetrahedra, and corners with two equivalent Si(3)O4 tetrahedra. Fe(1) is bonded in a 4-coordinate geometry to one O(1), one O(3), one O(4), and one O(5) atom. There are three inequivalent Si sites. In the first Si site, Si(1) is bonded to one O(1), one O(3), one O(6), and one O(7) atom to form SiO4 tetrahedra that share  a cornercorner with one Si(2)O4 tetrahedra,  a cornercorner with one Si(3)O4 tetrahedra, and corners with two equivalent Li(2)O4 trigonal pyramids. In the second Si site, Si(2) is bonded to one O(2), one O(4), one O(6), and one O(8) atom to form SiO4 tetrahedra that share  a cornercorner with one Si(1)O4 tetrahedra, corners with two equivalent Si(3)O4 tetrahedra, and  a cornercorner with one Li(2)O4 trigonal pyramid. In the third Si site, Si(3) is bonded to one O(2), one O(5), one O(7), and one O(8) atom to form SiO4 tetrahedra that share  a cornercorner with one Si(1)O4 tetrahedra, corners with two equivalent Si(2)O4 tetrahedra, and corners with two equivalent Li(2)O4 trigonal pyramids. There are eight 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 Si(1) atom. In the second O site, O(2) is bonded in a distorted trigonal planar geometry to one Li(1), one Si(2), and one Si(3) atom. In the third O site, O(3) is bonded in a distorted trigonal pyramidal geometry to one Li(1), one Li(2), one Fe(1), and one Si(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 Si(2) atom. In the fifth O site, O(5) is bonded in a trigonal planar geometry to one Li(2), one Fe(1), and one Si(3) atom. In the sixth O site, O(6) is bonded in a distorted bent 150 degrees geometry to one Si(1) and one Si(2) atom. In the seventh O site, O(7) is bonded in a trigonal non-coplanar geometry to one Li(1), one Si(1), and one Si(3) atom. In the eighth O site, O(8) is bonded in a distorted trigonal planar geometry to one Li(2), one Si(2), and one Si(3) atom.
Li2FeSi3O8 crystallizes in the triclinic P1 space group. There are two inequivalent Li sites. In the first Li site, Li(1) is bonded in a distorted see-saw-like geometry to one O(2), one O(3), one O(4), and one O(7) atom. The Li(1)-O(2) bond length is 2.47 Å. The Li(1)-O(3) bond length is 1.93 Å. The Li(1)-O(4) bond length is 2.01 Å. The Li(1)-O(7) bond length is 2.13 Å. In the second Li site, Li(2) is bonded to one O(1), one O(3), one O(5), and one O(8) atom to form distorted LiO4 trigonal pyramids that share  a cornercorner with one Si(2)O4 tetrahedra, corners with two equivalent Si(1)O4 tetrahedra, and corners with two equivalent Si(3)O4 tetrahedra. The Li(2)-O(1) bond length is 2.02 Å. The Li(2)-O(3) bond length is 1.97 Å. The Li(2)-O(5) bond length is 2.01 Å. The Li(2)-O(8) bond length is 2.52 Å. Fe(1) is bonded in a 4-coordinate geometry to one O(1), one O(3), one O(4), and one O(5) atom. The Fe(1)-O(1) bond length is 2.03 Å. The Fe(1)-O(3) bond length is 2.10 Å. The Fe(1)-O(4) bond length is 2.02 Å. The Fe(1)-O(5) bond length is 1.98 Å. There are three inequivalent Si sites. In the first Si site, Si(1) is bonded to one O(1), one O(3), one O(6), and one O(7) atom to form SiO4 tetrahedra that share  a cornercorner with one Si(2)O4 tetrahedra,  a cornercorner with one Si(3)O4 tetrahedra, and corners with two equivalent Li(2)O4 trigonal pyramids. The Si(1)-O(1) bond length is 1.61 Å. The Si(1)-O(3) bond length is 1.62 Å. The Si(1)-O(6) bond length is 1.67 Å. The Si(1)-O(7) bond length is 1.69 Å. In the second Si site, Si(2) is bonded to one O(2), one O(4), one O(6), and one O(8) atom to form SiO4 tetrahedra that share  a cornercorner with one Si(1)O4 tetrahedra, corners with two equivalent Si(3)O4 tetrahedra, and  a cornercorner with one Li(2)O4 trigonal pyramid. The Si(2)-O(2) bond length is 1.69 Å. The Si(2)-O(4) bond length is 1.60 Å. The Si(2)-O(6) bond length is 1.64 Å. The Si(2)-O(8) bond length is 1.67 Å. In the third Si site, Si(3) is bonded to one O(2), one O(5), one O(7), and one O(8) atom to form SiO4 tetrahedra that share  a cornercorner with one Si(1)O4 tetrahedra, corners with two equivalent Si(2)O4 tetrahedra, and corners with two equivalent Li(2)O4 trigonal pyramids. The Si(3)-O(2) bond length is 1.67 Å. The Si(3)-O(5) bond length is 1.60 Å. The Si(3)-O(7) bond length is 1.65 Å. The Si(3)-O(8) bond length is 1.67 Å. There are eight 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 Si(1) atom. In the second O site, O(2) is bonded in a distorted trigonal planar geometry to one Li(1), one Si(2), and one Si(3) atom. In the third O site, O(3) is bonded in a distorted trigonal pyramidal geometry to one Li(1), one Li(2), one Fe(1), and one Si(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 Si(2) atom. In the fifth O site, O(5) is bonded in a trigonal planar geometry to one Li(2), one Fe(1), and one Si(3) atom. In the sixth O site, O(6) is bonded in a distorted bent 150 degrees geometry to one Si(1) and one Si(2) atom. In the seventh O site, O(7) is bonded in a trigonal non-coplanar geometry to one Li(1), one Si(1), and one Si(3) atom. In the eighth O site, O(8) is bonded in a distorted trigonal planar geometry to one Li(2), one Si(2), and one Si(3) atom.