Li3Fe2(SiO4)2 is Clathrate-derived structured and crystallizes in the monoclinic Pc space group. There are three inequivalent Li sites. In the first Li site, Li(1) is bonded to one O(1), one O(2), one O(6), and one O(8) atom to form LiO4 tetrahedra that share corners with two equivalent Li(2)O4 tetrahedra, corners with two equivalent Fe(2)O4 tetrahedra, corners with two equivalent Si(1)O4 tetrahedra, corners with two equivalent Si(2)O4 tetrahedra, and  an edgeedge with one Li(3)O4 tetrahedra. In the second Li site, Li(2) is bonded to one O(1), one O(4), one O(6), and one O(7) atom to form distorted LiO4 tetrahedra that share corners with two equivalent Li(1)O4 tetrahedra, corners with two equivalent Li(3)O4 tetrahedra, corners with two equivalent Fe(1)O4 tetrahedra, corners with two equivalent Fe(2)O4 tetrahedra, corners with two equivalent Si(1)O4 tetrahedra, and corners with two equivalent Si(2)O4 tetrahedra. In the third Li site, Li(3) is bonded to one O(1), one O(3), one O(7), and one O(8) atom to form LiO4 tetrahedra that share corners with two equivalent Li(2)O4 tetrahedra, corners with two equivalent Fe(1)O4 tetrahedra, corners with two equivalent Si(1)O4 tetrahedra, corners with two equivalent Si(2)O4 tetrahedra, and  an edgeedge with one Li(1)O4 tetrahedra. There are two inequivalent Fe sites. In the first Fe site, Fe(1) is bonded to one O(3), one O(4), one O(5), and one O(7) atom to form distorted FeO4 tetrahedra that share corners with two equivalent Li(2)O4 tetrahedra, corners with two equivalent Li(3)O4 tetrahedra, corners with two equivalent Si(1)O4 tetrahedra, corners with two equivalent Si(2)O4 tetrahedra, and  an edgeedge with one Fe(2)O4 tetrahedra. In the second Fe site, Fe(2) is bonded to one O(2), one O(4), one O(5), and one O(6) atom to form FeO4 tetrahedra that share corners with two equivalent Li(1)O4 tetrahedra, corners with two equivalent Li(2)O4 tetrahedra, corners with two equivalent Si(1)O4 tetrahedra, corners with two equivalent Si(2)O4 tetrahedra, and  an edgeedge with one Fe(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(3), and one O(4) atom to form SiO4 tetrahedra that share corners with two equivalent Li(1)O4 tetrahedra, corners with two equivalent Li(2)O4 tetrahedra, corners with two equivalent Li(3)O4 tetrahedra, corners with two equivalent Fe(1)O4 tetrahedra, and corners with two equivalent Fe(2)O4 tetrahedra. In the second Si site, Si(2) is bonded to one O(5), one O(6), one O(7), and one O(8) atom to form SiO4 tetrahedra that share corners with two equivalent Li(1)O4 tetrahedra, corners with two equivalent Li(2)O4 tetrahedra, corners with two equivalent Li(3)O4 tetrahedra, corners with two equivalent Fe(1)O4 tetrahedra, and corners with two equivalent Fe(2)O4 tetrahedra. There are eight inequivalent O sites. In the first O site, O(1) is bonded to one Li(1), one Li(2), one Li(3), and one Si(1) atom to form OLi3Si tetrahedra that share corners with two equivalent O(6)Li2FeSi tetrahedra, corners with two equivalent O(7)Li2FeSi tetrahedra, and corners with two equivalent O(4)LiFe2Si trigonal pyramids. In the second O site, O(2) is bonded in a trigonal planar geometry to one Li(1), one Fe(2), and one Si(1) atom. In the third O site, O(3) is bonded in a trigonal planar geometry to one Li(3), one Fe(1), and one Si(1) atom. In the fourth O site, O(4) is bonded to one Li(2), one Fe(1), one Fe(2), and one Si(1) atom to form distorted OLiFe2Si trigonal pyramids that share corners with two equivalent O(6)Li2FeSi tetrahedra, corners with two equivalent O(7)Li2FeSi tetrahedra, and corners with two equivalent O(1)Li3Si tetrahedra. In the fifth O site, O(5) is bonded in a distorted T-shaped geometry to one Fe(1), one Fe(2), and one Si(2) atom. In the sixth O site, O(6) is bonded to one Li(1), one Li(2), one Fe(2), and one Si(2) atom to form OLi2FeSi tetrahedra that share corners with two equivalent O(7)Li2FeSi tetrahedra, corners with two equivalent O(1)Li3Si tetrahedra, and corners with two equivalent O(4)LiFe2Si trigonal pyramids. In the seventh O site, O(7) is bonded to one Li(2), one Li(3), one Fe(1), and one Si(2) atom to form OLi2FeSi tetrahedra that share corners with two equivalent O(6)Li2FeSi tetrahedra, corners with two equivalent O(1)Li3Si tetrahedra, and corners with two equivalent O(4)LiFe2Si trigonal pyramids. In the eighth O site, O(8) is bonded in a distorted trigonal planar geometry to one Li(1), one Li(3), and one Si(2) atom.
Li3Fe2(SiO4)2 is Clathrate-derived structured and crystallizes in the monoclinic Pc space group. There are three inequivalent Li sites. In the first Li site, Li(1) is bonded to one O(1), one O(2), one O(6), and one O(8) atom to form LiO4 tetrahedra that share corners with two equivalent Li(2)O4 tetrahedra, corners with two equivalent Fe(2)O4 tetrahedra, corners with two equivalent Si(1)O4 tetrahedra, corners with two equivalent Si(2)O4 tetrahedra, and  an edgeedge with one Li(3)O4 tetrahedra. The Li(1)-O(1) bond length is 2.02 Å. The Li(1)-O(2) bond length is 2.00 Å. The Li(1)-O(6) bond length is 2.23 Å. The Li(1)-O(8) bond length is 1.92 Å. In the second Li site, Li(2) is bonded to one O(1), one O(4), one O(6), and one O(7) atom to form distorted LiO4 tetrahedra that share corners with two equivalent Li(1)O4 tetrahedra, corners with two equivalent Li(3)O4 tetrahedra, corners with two equivalent Fe(1)O4 tetrahedra, corners with two equivalent Fe(2)O4 tetrahedra, corners with two equivalent Si(1)O4 tetrahedra, and corners with two equivalent Si(2)O4 tetrahedra. The Li(2)-O(1) bond length is 1.95 Å. The Li(2)-O(4) bond length is 2.44 Å. The Li(2)-O(6) bond length is 2.09 Å. The Li(2)-O(7) bond length is 2.00 Å. In the third Li site, Li(3) is bonded to one O(1), one O(3), one O(7), and one O(8) atom to form LiO4 tetrahedra that share corners with two equivalent Li(2)O4 tetrahedra, corners with two equivalent Fe(1)O4 tetrahedra, corners with two equivalent Si(1)O4 tetrahedra, corners with two equivalent Si(2)O4 tetrahedra, and  an edgeedge with one Li(1)O4 tetrahedra. The Li(3)-O(1) bond length is 2.00 Å. The Li(3)-O(3) bond length is 1.95 Å. The Li(3)-O(7) bond length is 2.08 Å. The Li(3)-O(8) bond length is 1.96 Å. There are two inequivalent Fe sites. In the first Fe site, Fe(1) is bonded to one O(3), one O(4), one O(5), and one O(7) atom to form distorted FeO4 tetrahedra that share corners with two equivalent Li(2)O4 tetrahedra, corners with two equivalent Li(3)O4 tetrahedra, corners with two equivalent Si(1)O4 tetrahedra, corners with two equivalent Si(2)O4 tetrahedra, and  an edgeedge with one Fe(2)O4 tetrahedra. The Fe(1)-O(3) bond length is 1.91 Å. The Fe(1)-O(4) bond length is 2.13 Å. The Fe(1)-O(5) bond length is 2.15 Å. The Fe(1)-O(7) bond length is 1.98 Å. In the second Fe site, Fe(2) is bonded to one O(2), one O(4), one O(5), and one O(6) atom to form FeO4 tetrahedra that share corners with two equivalent Li(1)O4 tetrahedra, corners with two equivalent Li(2)O4 tetrahedra, corners with two equivalent Si(1)O4 tetrahedra, corners with two equivalent Si(2)O4 tetrahedra, and  an edgeedge with one Fe(1)O4 tetrahedra. The Fe(2)-O(2) bond length is 1.86 Å. The Fe(2)-O(4) bond length is 1.96 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(3), and one O(4) atom to form SiO4 tetrahedra that share corners with two equivalent Li(1)O4 tetrahedra, corners with two equivalent Li(2)O4 tetrahedra, corners with two equivalent Li(3)O4 tetrahedra, corners with two equivalent Fe(1)O4 tetrahedra, and corners with two equivalent Fe(2)O4 tetrahedra. The Si(1)-O(1) bond length is 1.62 Å. The Si(1)-O(2) bond length is 1.66 Å. The Si(1)-O(3) bond length is 1.63 Å. The Si(1)-O(4) bond length is 1.72 Å. In the second Si site, Si(2) is bonded to one O(5), one O(6), one O(7), and one O(8) atom to form SiO4 tetrahedra that share corners with two equivalent Li(1)O4 tetrahedra, corners with two equivalent Li(2)O4 tetrahedra, corners with two equivalent Li(3)O4 tetrahedra, corners with two equivalent Fe(1)O4 tetrahedra, and corners with two equivalent Fe(2)O4 tetrahedra. The Si(2)-O(5) bond length is 1.69 Å. The Si(2)-O(6) bond length is 1.70 Å. The Si(2)-O(7) bond length is 1.67 Å. The Si(2)-O(8) bond length is 1.58 Å. There are eight inequivalent O sites. In the first O site, O(1) is bonded to one Li(1), one Li(2), one Li(3), and one Si(1) atom to form OLi3Si tetrahedra that share corners with two equivalent O(6)Li2FeSi tetrahedra, corners with two equivalent O(7)Li2FeSi tetrahedra, and corners with two equivalent O(4)LiFe2Si trigonal pyramids. In the second O site, O(2) is bonded in a trigonal planar geometry to one Li(1), one Fe(2), and one Si(1) atom. In the third O site, O(3) is bonded in a trigonal planar geometry to one Li(3), one Fe(1), and one Si(1) atom. In the fourth O site, O(4) is bonded to one Li(2), one Fe(1), one Fe(2), and one Si(1) atom to form distorted OLiFe2Si trigonal pyramids that share corners with two equivalent O(6)Li2FeSi tetrahedra, corners with two equivalent O(7)Li2FeSi tetrahedra, and corners with two equivalent O(1)Li3Si tetrahedra. In the fifth O site, O(5) is bonded in a distorted T-shaped geometry to one Fe(1), one Fe(2), and one Si(2) atom. In the sixth O site, O(6) is bonded to one Li(1), one Li(2), one Fe(2), and one Si(2) atom to form OLi2FeSi tetrahedra that share corners with two equivalent O(7)Li2FeSi tetrahedra, corners with two equivalent O(1)Li3Si tetrahedra, and corners with two equivalent O(4)LiFe2Si trigonal pyramids. In the seventh O site, O(7) is bonded to one Li(2), one Li(3), one Fe(1), and one Si(2) atom to form OLi2FeSi tetrahedra that share corners with two equivalent O(6)Li2FeSi tetrahedra, corners with two equivalent O(1)Li3Si tetrahedra, and corners with two equivalent O(4)LiFe2Si trigonal pyramids. In the eighth O site, O(8) is bonded in a distorted trigonal planar geometry to one Li(1), one Li(3), and one Si(2) atom.