Li7Fe3(SiO6)2 is Caswellsilverite-derived structured and crystallizes in the monoclinic C2/m space group. There are three inequivalent Li sites. In the first Li site, Li(1) is bonded to one O(1), one O(4), two equivalent O(2), and two equivalent O(3) atoms to form LiO6 octahedra that share  a cornercorner with one Li(3)O6 octahedra,  a cornercorner with one Fe(1)O6 octahedra, corners with two equivalent Fe(2)O6 octahedra, corners with two equivalent Si(1)O6 octahedra,  an edgeedge with one Li(3)O6 octahedra,  an edgeedge with one Fe(1)O6 octahedra, edges with two equivalent Fe(2)O6 octahedra, edges with two equivalent Si(1)O6 octahedra, and edges with six equivalent Li(2)O6 octahedra. The corner-sharing octahedral tilt angles range from 3-15°. In the second Li site, Li(2) is bonded to one O(1), one O(4), two equivalent O(2), and two equivalent O(3) atoms to form LiO6 octahedra that share  a cornercorner with one Li(3)O6 octahedra,  a cornercorner with one Fe(1)O6 octahedra, corners with two equivalent Fe(2)O6 octahedra, corners with two equivalent Si(1)O6 octahedra,  an edgeedge with one Li(3)O6 octahedra,  an edgeedge with one Fe(1)O6 octahedra, edges with two equivalent Fe(2)O6 octahedra, edges with two equivalent Si(1)O6 octahedra, edges with three equivalent Li(1)O6 octahedra, and edges with three equivalent Li(2)O6 octahedra. The corner-sharing octahedral tilt angles range from 3-15°. In the third Li site, Li(3) is bonded to two equivalent O(1) and four equivalent O(2) atoms to form LiO6 octahedra that share corners with two equivalent Li(1)O6 octahedra, corners with four equivalent Li(2)O6 octahedra, edges with two equivalent Li(1)O6 octahedra, edges with four equivalent Li(2)O6 octahedra, and edges with six equivalent Si(1)O6 octahedra. The corner-sharing octahedral tilt angles are 15°. There are two inequivalent Fe sites. In the first Fe site, Fe(1) is bonded to two equivalent O(4) and four equivalent O(3) atoms to form FeO6 octahedra that share corners with two equivalent Li(1)O6 octahedra, corners with four equivalent Li(2)O6 octahedra, edges with two equivalent Li(1)O6 octahedra, edges with four equivalent Li(2)O6 octahedra, and edges with six equivalent Fe(2)O6 octahedra. The corner-sharing octahedral tilt angles range from 3-4°. In the second Fe site, Fe(2) is bonded to two equivalent O(4) and four equivalent O(3) atoms to form FeO6 octahedra that share corners with two equivalent Li(1)O6 octahedra, corners with four equivalent Li(2)O6 octahedra, edges with two equivalent Li(1)O6 octahedra, edges with three equivalent Fe(1)O6 octahedra, edges with three equivalent Fe(2)O6 octahedra, and edges with four equivalent Li(2)O6 octahedra. The corner-sharing octahedral tilt angles range from 3-4°. Si(1) is bonded to two equivalent O(1) and four equivalent O(2) atoms to form SiO6 octahedra that share corners with two equivalent Li(1)O6 octahedra, corners with four equivalent Li(2)O6 octahedra, edges with two equivalent Li(1)O6 octahedra, edges with three equivalent Li(3)O6 octahedra, edges with three equivalent Si(1)O6 octahedra, and edges with four equivalent Li(2)O6 octahedra. The corner-sharing octahedral tilt angles are 12°. There are four inequivalent O sites. In the first O site, O(1) is bonded to one Li(1), one Li(3), two equivalent Li(2), and two equivalent Si(1) atoms to form OLi4Si2 octahedra that share  a cornercorner with one O(4)Li3Fe3 octahedra,  a cornercorner with one O(1)Li4Si2 octahedra, corners with two equivalent O(3)Li3Fe3 octahedra, corners with two equivalent O(2)Li4Si2 octahedra,  an edgeedge with one O(4)Li3Fe3 octahedra,  an edgeedge with one O(1)Li4Si2 octahedra, edges with two equivalent O(3)Li3Fe3 octahedra, and edges with eight equivalent O(2)Li4Si2 octahedra. The corner-sharing octahedral tilt angles range from 0-11°. In the second O site, O(2) is bonded to one Li(1), one Li(3), two equivalent Li(2), and two equivalent Si(1) atoms to form OLi4Si2 octahedra that share  a cornercorner with one O(4)Li3Fe3 octahedra,  a cornercorner with one O(1)Li4Si2 octahedra, corners with two equivalent O(3)Li3Fe3 octahedra, corners with two equivalent O(2)Li4Si2 octahedra,  an edgeedge with one O(4)Li3Fe3 octahedra, edges with two equivalent O(3)Li3Fe3 octahedra, edges with four equivalent O(1)Li4Si2 octahedra, and edges with five equivalent O(2)Li4Si2 octahedra. The corner-sharing octahedral tilt angles range from 0-11°. In the third O site, O(3) is bonded to one Li(1), two equivalent Li(2), one Fe(1), and two equivalent Fe(2) atoms to form OLi3Fe3 octahedra that share  a cornercorner with one O(4)Li3Fe3 octahedra,  a cornercorner with one O(1)Li4Si2 octahedra, corners with two equivalent O(3)Li3Fe3 octahedra, corners with two equivalent O(2)Li4Si2 octahedra,  an edgeedge with one O(1)Li4Si2 octahedra, edges with two equivalent O(2)Li4Si2 octahedra, edges with four equivalent O(4)Li3Fe3 octahedra, and edges with five equivalent O(3)Li3Fe3 octahedra. The corner-sharing octahedral tilt angles range from 0-6°. In the fourth O site, O(4) is bonded to one Li(1), two equivalent Li(2), one Fe(1), and two equivalent Fe(2) atoms to form OLi3Fe3 octahedra that share  a cornercorner with one O(4)Li3Fe3 octahedra,  a cornercorner with one O(1)Li4Si2 octahedra, corners with two equivalent O(3)Li3Fe3 octahedra, corners with two equivalent O(2)Li4Si2 octahedra,  an edgeedge with one O(4)Li3Fe3 octahedra,  an edgeedge with one O(1)Li4Si2 octahedra, edges with two equivalent O(2)Li4Si2 octahedra, and edges with eight equivalent O(3)Li3Fe3 octahedra. The corner-sharing octahedral tilt angles range from 0-4°.
Li7Fe3(SiO6)2 is Caswellsilverite-derived structured and crystallizes in the monoclinic C2/m space group. There are three inequivalent Li sites. In the first Li site, Li(1) is bonded to one O(1), one O(4), two equivalent O(2), and two equivalent O(3) atoms to form LiO6 octahedra that share  a cornercorner with one Li(3)O6 octahedra,  a cornercorner with one Fe(1)O6 octahedra, corners with two equivalent Fe(2)O6 octahedra, corners with two equivalent Si(1)O6 octahedra,  an edgeedge with one Li(3)O6 octahedra,  an edgeedge with one Fe(1)O6 octahedra, edges with two equivalent Fe(2)O6 octahedra, edges with two equivalent Si(1)O6 octahedra, and edges with six equivalent Li(2)O6 octahedra. The corner-sharing octahedral tilt angles range from 3-15°. The Li(1)-O(1) bond length is 2.02 Å. The Li(1)-O(4) bond length is 2.10 Å. Both Li(1)-O(2) bond lengths are 2.23 Å. Both Li(1)-O(3) bond lengths are 2.14 Å. In the second Li site, Li(2) is bonded to one O(1), one O(4), two equivalent O(2), and two equivalent O(3) atoms to form LiO6 octahedra that share  a cornercorner with one Li(3)O6 octahedra,  a cornercorner with one Fe(1)O6 octahedra, corners with two equivalent Fe(2)O6 octahedra, corners with two equivalent Si(1)O6 octahedra,  an edgeedge with one Li(3)O6 octahedra,  an edgeedge with one Fe(1)O6 octahedra, edges with two equivalent Fe(2)O6 octahedra, edges with two equivalent Si(1)O6 octahedra, edges with three equivalent Li(1)O6 octahedra, and edges with three equivalent Li(2)O6 octahedra. The corner-sharing octahedral tilt angles range from 3-15°. The Li(2)-O(1) bond length is 2.23 Å. The Li(2)-O(4) bond length is 2.10 Å. There is one shorter (2.02 Å) and one longer (2.23 Å) Li(2)-O(2) bond length. Both Li(2)-O(3) bond lengths are 2.15 Å. In the third Li site, Li(3) is bonded to two equivalent O(1) and four equivalent O(2) atoms to form LiO6 octahedra that share corners with two equivalent Li(1)O6 octahedra, corners with four equivalent Li(2)O6 octahedra, edges with two equivalent Li(1)O6 octahedra, edges with four equivalent Li(2)O6 octahedra, and edges with six equivalent Si(1)O6 octahedra. The corner-sharing octahedral tilt angles are 15°. Both Li(3)-O(1) bond lengths are 2.11 Å. All Li(3)-O(2) bond lengths are 2.11 Å. There are two inequivalent Fe sites. In the first Fe site, Fe(1) is bonded to two equivalent O(4) and four equivalent O(3) atoms to form FeO6 octahedra that share corners with two equivalent Li(1)O6 octahedra, corners with four equivalent Li(2)O6 octahedra, edges with two equivalent Li(1)O6 octahedra, edges with four equivalent Li(2)O6 octahedra, and edges with six equivalent Fe(2)O6 octahedra. The corner-sharing octahedral tilt angles range from 3-4°. Both Fe(1)-O(4) bond lengths are 2.04 Å. All Fe(1)-O(3) bond lengths are 2.02 Å. In the second Fe site, Fe(2) is bonded to two equivalent O(4) and four equivalent O(3) atoms to form FeO6 octahedra that share corners with two equivalent Li(1)O6 octahedra, corners with four equivalent Li(2)O6 octahedra, edges with two equivalent Li(1)O6 octahedra, edges with three equivalent Fe(1)O6 octahedra, edges with three equivalent Fe(2)O6 octahedra, and edges with four equivalent Li(2)O6 octahedra. The corner-sharing octahedral tilt angles range from 3-4°. Both Fe(2)-O(4) bond lengths are 2.04 Å. All Fe(2)-O(3) bond lengths are 2.02 Å. Si(1) is bonded to two equivalent O(1) and four equivalent O(2) atoms to form SiO6 octahedra that share corners with two equivalent Li(1)O6 octahedra, corners with four equivalent Li(2)O6 octahedra, edges with two equivalent Li(1)O6 octahedra, edges with three equivalent Li(3)O6 octahedra, edges with three equivalent Si(1)O6 octahedra, and edges with four equivalent Li(2)O6 octahedra. The corner-sharing octahedral tilt angles are 12°. Both Si(1)-O(1) bond lengths are 1.86 Å. All Si(1)-O(2) bond lengths are 1.86 Å. There are four inequivalent O sites. In the first O site, O(1) is bonded to one Li(1), one Li(3), two equivalent Li(2), and two equivalent Si(1) atoms to form OLi4Si2 octahedra that share  a cornercorner with one O(4)Li3Fe3 octahedra,  a cornercorner with one O(1)Li4Si2 octahedra, corners with two equivalent O(3)Li3Fe3 octahedra, corners with two equivalent O(2)Li4Si2 octahedra,  an edgeedge with one O(4)Li3Fe3 octahedra,  an edgeedge with one O(1)Li4Si2 octahedra, edges with two equivalent O(3)Li3Fe3 octahedra, and edges with eight equivalent O(2)Li4Si2 octahedra. The corner-sharing octahedral tilt angles range from 0-11°. In the second O site, O(2) is bonded to one Li(1), one Li(3), two equivalent Li(2), and two equivalent Si(1) atoms to form OLi4Si2 octahedra that share  a cornercorner with one O(4)Li3Fe3 octahedra,  a cornercorner with one O(1)Li4Si2 octahedra, corners with two equivalent O(3)Li3Fe3 octahedra, corners with two equivalent O(2)Li4Si2 octahedra,  an edgeedge with one O(4)Li3Fe3 octahedra, edges with two equivalent O(3)Li3Fe3 octahedra, edges with four equivalent O(1)Li4Si2 octahedra, and edges with five equivalent O(2)Li4Si2 octahedra. The corner-sharing octahedral tilt angles range from 0-11°. In the third O site, O(3) is bonded to one Li(1), two equivalent Li(2), one Fe(1), and two equivalent Fe(2) atoms to form OLi3Fe3 octahedra that share  a cornercorner with one O(4)Li3Fe3 octahedra,  a cornercorner with one O(1)Li4Si2 octahedra, corners with two equivalent O(3)Li3Fe3 octahedra, corners with two equivalent O(2)Li4Si2 octahedra,  an edgeedge with one O(1)Li4Si2 octahedra, edges with two equivalent O(2)Li4Si2 octahedra, edges with four equivalent O(4)Li3Fe3 octahedra, and edges with five equivalent O(3)Li3Fe3 octahedra. The corner-sharing octahedral tilt angles range from 0-6°. In the fourth O site, O(4) is bonded to one Li(1), two equivalent Li(2), one Fe(1), and two equivalent Fe(2) atoms to form OLi3Fe3 octahedra that share  a cornercorner with one O(4)Li3Fe3 octahedra,  a cornercorner with one O(1)Li4Si2 octahedra, corners with two equivalent O(3)Li3Fe3 octahedra, corners with two equivalent O(2)Li4Si2 octahedra,  an edgeedge with one O(4)Li3Fe3 octahedra,  an edgeedge with one O(1)Li4Si2 octahedra, edges with two equivalent O(2)Li4Si2 octahedra, and edges with eight equivalent O(3)Li3Fe3 octahedra. The corner-sharing octahedral tilt angles range from 0-4°.