Li4Fe3(SiO4)3 crystallizes in the monoclinic C2 space group. There are two inequivalent Li sites. In the first Li site, Li(1) is bonded to one O(1), one O(6), and two equivalent O(3) atoms to form LiO4 tetrahedra that share  a cornercorner with one Si(1)O4 tetrahedra, corners with two equivalent Li(1)O4 tetrahedra, corners with three equivalent Si(2)O4 tetrahedra, and corners with four equivalent Fe(2)O4 tetrahedra. In the second Li site, Li(2) is bonded to one O(2), one O(5), and two equivalent O(4) atoms to form LiO4 tetrahedra that share  a cornercorner with one Fe(2)O4 tetrahedra, corners with two equivalent Li(2)O4 tetrahedra, corners with three equivalent Fe(1)O4 tetrahedra, and corners with four equivalent Si(1)O4 tetrahedra. There are two inequivalent Fe sites. In the first Fe site, Fe(1) is bonded to two equivalent O(2) and two equivalent O(4) atoms to form FeO4 tetrahedra that share corners with four equivalent Si(1)O4 tetrahedra and corners with six equivalent Li(2)O4 tetrahedra. In the second Fe site, Fe(2) is bonded to one O(1), one O(3), one O(5), and one O(6) atom to form FeO4 tetrahedra that share  a cornercorner with one Li(2)O4 tetrahedra, corners with two equivalent Si(1)O4 tetrahedra, corners with two equivalent Si(2)O4 tetrahedra, and corners with four equivalent Li(1)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(5) atom to form SiO4 tetrahedra that share  a cornercorner with one Li(1)O4 tetrahedra, corners with two equivalent Fe(1)O4 tetrahedra, corners with two equivalent Fe(2)O4 tetrahedra, and corners with four equivalent Li(2)O4 tetrahedra. In the second Si site, Si(2) is bonded to two equivalent O(3) and two equivalent O(6) atoms to form SiO4 tetrahedra that share corners with four equivalent Fe(2)O4 tetrahedra and corners with six equivalent Li(1)O4 tetrahedra. There are six inequivalent O sites. In the first O site, O(1) is bonded in a trigonal non-coplanar geometry to one Li(1), one Fe(2), and one Si(1) atom. In the second O site, O(2) is bonded in a trigonal non-coplanar geometry to one Li(2), one Fe(1), and one Si(1) atom. In the third O site, O(3) is bonded to two equivalent Li(1), one Fe(2), and one Si(2) atom to form corner-sharing OLi2FeSi tetrahedra. In the fourth O site, O(4) is bonded to two equivalent Li(2), one Fe(1), and one Si(1) atom to form corner-sharing OLi2FeSi tetrahedra. In the fifth O site, O(5) is bonded in a trigonal non-coplanar geometry to one Li(2), one Fe(2), and one Si(1) atom. In the sixth O site, O(6) is bonded in a trigonal non-coplanar geometry to one Li(1), one Fe(2), and one Si(2) atom.
Li4Fe3(SiO4)3 crystallizes in the monoclinic C2 space group. There are two inequivalent Li sites. In the first Li site, Li(1) is bonded to one O(1), one O(6), and two equivalent O(3) atoms to form LiO4 tetrahedra that share  a cornercorner with one Si(1)O4 tetrahedra, corners with two equivalent Li(1)O4 tetrahedra, corners with three equivalent Si(2)O4 tetrahedra, and corners with four equivalent Fe(2)O4 tetrahedra. The Li(1)-O(1) bond length is 1.95 Å. The Li(1)-O(6) bond length is 1.95 Å. There is one shorter (2.03 Å) and one longer (2.04 Å) Li(1)-O(3) bond length. In the second Li site, Li(2) is bonded to one O(2), one O(5), and two equivalent O(4) atoms to form LiO4 tetrahedra that share  a cornercorner with one Fe(2)O4 tetrahedra, corners with two equivalent Li(2)O4 tetrahedra, corners with three equivalent Fe(1)O4 tetrahedra, and corners with four equivalent Si(1)O4 tetrahedra. The Li(2)-O(2) bond length is 1.94 Å. The Li(2)-O(5) bond length is 1.94 Å. There is one shorter (2.01 Å) and one longer (2.02 Å) Li(2)-O(4) bond length. There are two inequivalent Fe sites. In the first Fe site, Fe(1) is bonded to two equivalent O(2) and two equivalent O(4) atoms to form FeO4 tetrahedra that share corners with four equivalent Si(1)O4 tetrahedra and corners with six equivalent Li(2)O4 tetrahedra. Both Fe(1)-O(2) bond lengths are 1.93 Å. Both Fe(1)-O(4) bond lengths are 1.98 Å. In the second Fe site, Fe(2) is bonded to one O(1), one O(3), one O(5), and one O(6) atom to form FeO4 tetrahedra that share  a cornercorner with one Li(2)O4 tetrahedra, corners with two equivalent Si(1)O4 tetrahedra, corners with two equivalent Si(2)O4 tetrahedra, and corners with four equivalent Li(1)O4 tetrahedra. The Fe(2)-O(1) bond length is 1.93 Å. The Fe(2)-O(3) bond length is 2.00 Å. The Fe(2)-O(5) bond length is 1.92 Å. The Fe(2)-O(6) 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(5) atom to form SiO4 tetrahedra that share  a cornercorner with one Li(1)O4 tetrahedra, corners with two equivalent Fe(1)O4 tetrahedra, corners with two equivalent Fe(2)O4 tetrahedra, and corners with four equivalent Li(2)O4 tetrahedra. The Si(1)-O(1) bond length is 1.65 Å. The Si(1)-O(2) bond length is 1.65 Å. The Si(1)-O(4) bond length is 1.68 Å. The Si(1)-O(5) bond length is 1.66 Å. In the second Si site, Si(2) is bonded to two equivalent O(3) and two equivalent O(6) atoms to form SiO4 tetrahedra that share corners with four equivalent Fe(2)O4 tetrahedra and corners with six equivalent Li(1)O4 tetrahedra. Both Si(2)-O(3) bond lengths are 1.67 Å. Both Si(2)-O(6) bond lengths are 1.65 Å. There are six inequivalent O sites. In the first O site, O(1) is bonded in a trigonal non-coplanar geometry to one Li(1), one Fe(2), and one Si(1) atom. In the second O site, O(2) is bonded in a trigonal non-coplanar geometry to one Li(2), one Fe(1), and one Si(1) atom. In the third O site, O(3) is bonded to two equivalent Li(1), one Fe(2), and one Si(2) atom to form corner-sharing OLi2FeSi tetrahedra. In the fourth O site, O(4) is bonded to two equivalent Li(2), one Fe(1), and one Si(1) atom to form corner-sharing OLi2FeSi tetrahedra. In the fifth O site, O(5) is bonded in a trigonal non-coplanar geometry to one Li(2), one Fe(2), and one Si(1) atom. In the sixth O site, O(6) is bonded in a trigonal non-coplanar geometry to one Li(1), one Fe(2), and one Si(2) atom.