Li2Fe2Si4O11 crystallizes in the triclinic P-1 space group. There are two inequivalent Li sites. In the first Li site, Li(1) is bonded to one O(8), one O(9), and two equivalent O(11) atoms to form distorted LiO4 tetrahedra that share  a cornercorner with one Si(3)O4 tetrahedra,  a cornercorner with one Si(4)O4 tetrahedra, corners with two equivalent Si(2)O4 tetrahedra, and  an edgeedge with one Li(1)O4 tetrahedra. In the second Li site, Li(2) is bonded in a 3-coordinate geometry to one O(11), one O(7), one O(8), and one O(9) atom. There are two inequivalent Fe sites. In the first Fe site, Fe(1) is bonded in a 4-coordinate geometry to one O(1), one O(10), one O(3), and one O(7) atom. In the second Fe site, Fe(2) is bonded in a 4-coordinate geometry to one O(1), one O(11), one O(3), and one O(9) atom. There are four inequivalent Si sites. In the first Si site, Si(1) is bonded to one O(1), one O(2), one O(3), and one O(4) atom to form corner-sharing SiO4 tetrahedra. In the second Si site, Si(2) is bonded to one O(10), one O(11), one O(4), and one O(5) atom to form SiO4 tetrahedra that share  a cornercorner with one Si(1)O4 tetrahedra,  a cornercorner with one Si(3)O4 tetrahedra,  a cornercorner with one Si(4)O4 tetrahedra, and corners with two equivalent Li(1)O4 tetrahedra. In the third Si site, Si(3) is bonded to one O(2), one O(5), one O(6), and one O(8) atom to form SiO4 tetrahedra that share  a cornercorner with one Li(1)O4 tetrahedra,  a cornercorner with one Si(1)O4 tetrahedra,  a cornercorner with one Si(2)O4 tetrahedra, and  a cornercorner with one Si(4)O4 tetrahedra. In the fourth Si site, Si(4) is bonded to one O(10), one O(6), one O(7), and one O(9) atom to form SiO4 tetrahedra that share  a cornercorner with one Li(1)O4 tetrahedra,  a cornercorner with one Si(2)O4 tetrahedra, and  a cornercorner with one Si(3)O4 tetrahedra. There are eleven inequivalent O sites. In the first O site, O(1) is bonded in a trigonal planar geometry to one Fe(1), one Fe(2), and one Si(1) atom. In the second O site, O(2) is bonded in a bent 120 degrees geometry to one Si(1) and one Si(3) atom. In the third O site, O(3) is bonded in a trigonal planar geometry to one Fe(1), one Fe(2), and one Si(1) atom. In the fourth O site, O(4) is bonded in a distorted bent 120 degrees geometry to one Si(1) and one Si(2) atom. In the fifth O site, O(5) is bonded in a distorted bent 120 degrees geometry to one Si(2) and one Si(3) atom. In the sixth O site, O(6) is bonded in a distorted bent 120 degrees geometry to one Si(3) and one Si(4) atom. In the seventh O site, O(7) is bonded in a distorted trigonal planar geometry to one Li(2), one Fe(1), and one Si(4) atom. In the eighth O site, O(8) is bonded in a distorted trigonal planar geometry to one Li(1), one Li(2), and one Si(3) atom. In the ninth O site, O(9) is bonded in a 4-coordinate geometry to one Li(1), one Li(2), one Fe(2), and one Si(4) atom. In the tenth O site, O(10) is bonded in a 3-coordinate geometry to one Fe(1), one Si(2), and one Si(4) atom. In the eleventh O site, O(11) is bonded in a 5-coordinate geometry to one Li(2), two equivalent Li(1), one Fe(2), and one Si(2) atom.
Li2Fe2Si4O11 crystallizes in the triclinic P-1 space group. There are two inequivalent Li sites. In the first Li site, Li(1) is bonded to one O(8), one O(9), and two equivalent O(11) atoms to form distorted LiO4 tetrahedra that share  a cornercorner with one Si(3)O4 tetrahedra,  a cornercorner with one Si(4)O4 tetrahedra, corners with two equivalent Si(2)O4 tetrahedra, and  an edgeedge with one Li(1)O4 tetrahedra. The Li(1)-O(8) bond length is 1.91 Å. The Li(1)-O(9) bond length is 1.95 Å. There is one shorter (2.06 Å) and one longer (2.08 Å) Li(1)-O(11) bond length. In the second Li site, Li(2) is bonded in a 3-coordinate geometry to one O(11), one O(7), one O(8), and one O(9) atom. The Li(2)-O(11) bond length is 2.07 Å. The Li(2)-O(7) bond length is 2.00 Å. The Li(2)-O(8) bond length is 1.91 Å. The Li(2)-O(9) bond length is 2.54 Å. There are two inequivalent Fe sites. In the first Fe site, Fe(1) is bonded in a 4-coordinate geometry to one O(1), one O(10), one O(3), and one O(7) atom. The Fe(1)-O(1) bond length is 2.07 Å. The Fe(1)-O(10) bond length is 2.46 Å. The Fe(1)-O(3) bond length is 2.17 Å. The Fe(1)-O(7) bond length is 1.98 Å. In the second Fe site, Fe(2) is bonded in a 4-coordinate geometry to one O(1), one O(11), one O(3), and one O(9) atom. The Fe(2)-O(1) bond length is 2.06 Å. The Fe(2)-O(11) bond length is 2.28 Å. The Fe(2)-O(3) bond length is 2.02 Å. The Fe(2)-O(9) bond length is 2.03 Å. There are four inequivalent Si sites. In the first Si site, Si(1) is bonded to one O(1), one O(2), one O(3), and one O(4) atom to form corner-sharing SiO4 tetrahedra. The Si(1)-O(1) bond length is 1.64 Å. The Si(1)-O(2) bond length is 1.63 Å. The Si(1)-O(3) bond length is 1.65 Å. The Si(1)-O(4) bond length is 1.66 Å. In the second Si site, Si(2) is bonded to one O(10), one O(11), one O(4), and one O(5) atom to form SiO4 tetrahedra that share  a cornercorner with one Si(1)O4 tetrahedra,  a cornercorner with one Si(3)O4 tetrahedra,  a cornercorner with one Si(4)O4 tetrahedra, and corners with two equivalent Li(1)O4 tetrahedra. The Si(2)-O(10) bond length is 1.66 Å. The Si(2)-O(11) bond length is 1.62 Å. The Si(2)-O(4) bond length is 1.65 Å. The Si(2)-O(5) bond length is 1.64 Å. In the third Si site, Si(3) is bonded to one O(2), one O(5), one O(6), and one O(8) atom to form SiO4 tetrahedra that share  a cornercorner with one Li(1)O4 tetrahedra,  a cornercorner with one Si(1)O4 tetrahedra,  a cornercorner with one Si(2)O4 tetrahedra, and  a cornercorner with one Si(4)O4 tetrahedra. The Si(3)-O(2) bond length is 1.65 Å. The Si(3)-O(5) bond length is 1.66 Å. The Si(3)-O(6) bond length is 1.65 Å. The Si(3)-O(8) bond length is 1.60 Å. In the fourth Si site, Si(4) is bonded to one O(10), one O(6), one O(7), and one O(9) atom to form SiO4 tetrahedra that share  a cornercorner with one Li(1)O4 tetrahedra,  a cornercorner with one Si(2)O4 tetrahedra, and  a cornercorner with one Si(3)O4 tetrahedra. The Si(4)-O(10) bond length is 1.69 Å. The Si(4)-O(6) bond length is 1.66 Å. The Si(4)-O(7) bond length is 1.62 Å. The Si(4)-O(9) bond length is 1.61 Å. There are eleven inequivalent O sites. In the first O site, O(1) is bonded in a trigonal planar geometry to one Fe(1), one Fe(2), and one Si(1) atom. In the second O site, O(2) is bonded in a bent 120 degrees geometry to one Si(1) and one Si(3) atom. In the third O site, O(3) is bonded in a trigonal planar geometry to one Fe(1), one Fe(2), and one Si(1) atom. In the fourth O site, O(4) is bonded in a distorted bent 120 degrees geometry to one Si(1) and one Si(2) atom. In the fifth O site, O(5) is bonded in a distorted bent 120 degrees geometry to one Si(2) and one Si(3) atom. In the sixth O site, O(6) is bonded in a distorted bent 120 degrees geometry to one Si(3) and one Si(4) atom. In the seventh O site, O(7) is bonded in a distorted trigonal planar geometry to one Li(2), one Fe(1), and one Si(4) atom. In the eighth O site, O(8) is bonded in a distorted trigonal planar geometry to one Li(1), one Li(2), and one Si(3) atom. In the ninth O site, O(9) is bonded in a 4-coordinate geometry to one Li(1), one Li(2), one Fe(2), and one Si(4) atom. In the tenth O site, O(10) is bonded in a 3-coordinate geometry to one Fe(1), one Si(2), and one Si(4) atom. In the eleventh O site, O(11) is bonded in a 5-coordinate geometry to one Li(2), two equivalent Li(1), one Fe(2), and one Si(2) atom.