Li4Fe9CoO20 crystallizes in the monoclinic P2/m space group. There are two inequivalent Li sites. In the first Li site, Li(1) is bonded to one O(5), one O(8), two equivalent O(6), and two equivalent O(7) atoms to form distorted LiO6 octahedra that share  a cornercorner with one Fe(1)O6 octahedra, corners with five equivalent Fe(3)O6 octahedra, edges with two equivalent Li(1)O6 octahedra, edges with two equivalent Fe(2)O6 octahedra, edges with two equivalent Fe(3)O6 octahedra, and edges with two equivalent Fe(4)O6 octahedra. The corner-sharing octahedral tilt angles range from 6-25°. In the second Li site, Li(2) is bonded to one O(10), one O(3), two equivalent O(1), and two equivalent O(9) atoms to form LiO6 octahedra that share  a cornercorner with one Fe(2)O6 octahedra, corners with five equivalent Fe(5)O6 octahedra, edges with two equivalent Li(2)O6 octahedra, edges with two equivalent Fe(1)O6 octahedra, edges with two equivalent Fe(5)O6 octahedra, and edges with two equivalent Co(1)O6 octahedra. The corner-sharing octahedral tilt angles range from 9-20°. There are five inequivalent Fe sites. In the first Fe site, Fe(1) is bonded to one O(1), one O(5), two equivalent O(2), and two equivalent O(3) atoms to form FeO6 octahedra that share  a cornercorner with one Li(1)O6 octahedra, edges with two equivalent Li(2)O6 octahedra, edges with two equivalent Fe(1)O6 octahedra, edges with two equivalent Fe(2)O6 octahedra, and edges with two equivalent Fe(5)O6 octahedra. The corner-sharing octahedral tilt angles are 25°. In the second Fe site, Fe(2) is bonded to one O(3), one O(7), two equivalent O(4), and two equivalent O(5) atoms to form FeO6 octahedra that share  a cornercorner with one Li(2)O6 octahedra, edges with two equivalent Li(1)O6 octahedra, edges with two equivalent Fe(1)O6 octahedra, edges with two equivalent Fe(2)O6 octahedra, and edges with two equivalent Fe(3)O6 octahedra. The corner-sharing octahedral tilt angles are 20°. In the third Fe site, Fe(3) is bonded to one O(4), one O(8), two equivalent O(6), and two equivalent O(7) atoms to form FeO6 octahedra that share corners with five equivalent Li(1)O6 octahedra, edges with two equivalent Li(1)O6 octahedra, edges with two equivalent Fe(2)O6 octahedra, edges with two equivalent Fe(3)O6 octahedra, and edges with two equivalent Fe(4)O6 octahedra. The corner-sharing octahedral tilt angles range from 6-9°. In the fourth Fe site, Fe(4) is bonded to two equivalent O(6) and four equivalent O(8) atoms to form FeO6 octahedra that share edges with two equivalent Fe(4)O6 octahedra, edges with four equivalent Li(1)O6 octahedra, and edges with four equivalent Fe(3)O6 octahedra. In the fifth Fe site, Fe(5) is bonded to one O(10), one O(2), two equivalent O(1), and two equivalent O(9) atoms to form FeO6 octahedra that share corners with five equivalent Li(2)O6 octahedra, edges with two equivalent Li(2)O6 octahedra, edges with two equivalent Fe(1)O6 octahedra, edges with two equivalent Fe(5)O6 octahedra, and edges with two equivalent Co(1)O6 octahedra. The corner-sharing octahedral tilt angles range from 9-16°. Co(1) is bonded to two equivalent O(9) and four equivalent O(10) atoms to form CoO6 octahedra that share edges with two equivalent Co(1)O6 octahedra, edges with four equivalent Li(2)O6 octahedra, and edges with four equivalent Fe(5)O6 octahedra. There are ten inequivalent O sites. In the first O site, O(1) is bonded to two equivalent Li(2), one Fe(1), and two equivalent Fe(5) atoms to form OLi2Fe3 square pyramids that share corners with four equivalent O(9)Li2Fe2Co square pyramids,  a cornercorner with one O(5)LiFe3 trigonal pyramid, edges with two equivalent O(9)Li2Fe2Co square pyramids, edges with two equivalent O(1)Li2Fe3 square pyramids, and edges with two equivalent O(3)LiFe3 trigonal pyramids. In the second O site, O(2) is bonded in a 3-coordinate geometry to one Fe(5) and two equivalent Fe(1) atoms. In the third O site, O(3) is bonded to one Li(2), one Fe(2), and two equivalent Fe(1) atoms to form OLiFe3 trigonal pyramids that share  a cornercorner with one O(7)Li2Fe3 square pyramid, corners with two equivalent O(9)Li2Fe2Co square pyramids, corners with two equivalent O(3)LiFe3 trigonal pyramids, edges with two equivalent O(1)Li2Fe3 square pyramids, and edges with two equivalent O(5)LiFe3 trigonal pyramids. In the fourth O site, O(4) is bonded in a distorted trigonal non-coplanar geometry to one Fe(3) and two equivalent Fe(2) atoms. In the fifth O site, O(5) is bonded to one Li(1), one Fe(1), and two equivalent Fe(2) atoms to form distorted OLiFe3 trigonal pyramids that share  a cornercorner with one O(1)Li2Fe3 square pyramid, corners with two equivalent O(6)Li2Fe3 square pyramids, corners with two equivalent O(5)LiFe3 trigonal pyramids, edges with two equivalent O(7)Li2Fe3 square pyramids, and edges with two equivalent O(3)LiFe3 trigonal pyramids. In the sixth O site, O(6) is bonded to two equivalent Li(1), one Fe(4), and two equivalent Fe(3) atoms to form OLi2Fe3 square pyramids that share  a cornercorner with one O(6)Li2Fe3 square pyramid, corners with four equivalent O(7)Li2Fe3 square pyramids, corners with two equivalent O(5)LiFe3 trigonal pyramids, edges with two equivalent O(6)Li2Fe3 square pyramids, and edges with two equivalent O(7)Li2Fe3 square pyramids. In the seventh O site, O(7) is bonded to two equivalent Li(1), one Fe(2), and two equivalent Fe(3) atoms to form OLi2Fe3 square pyramids that share corners with four equivalent O(6)Li2Fe3 square pyramids,  a cornercorner with one O(3)LiFe3 trigonal pyramid, edges with two equivalent O(6)Li2Fe3 square pyramids, edges with two equivalent O(7)Li2Fe3 square pyramids, and edges with two equivalent O(5)LiFe3 trigonal pyramids. In the eighth O site, O(8) is bonded in a rectangular see-saw-like geometry to one Li(1), one Fe(3), and two equivalent Fe(4) atoms. In the ninth O site, O(9) is bonded to two equivalent Li(2), two equivalent Fe(5), and one Co(1) atom to form OLi2Fe2Co square pyramids that share  a cornercorner with one O(9)Li2Fe2Co square pyramid, corners with four equivalent O(1)Li2Fe3 square pyramids, corners with two equivalent O(3)LiFe3 trigonal pyramids, edges with two equivalent O(9)Li2Fe2Co square pyramids, and edges with two equivalent O(1)Li2Fe3 square pyramids. In the tenth O site, O(10) is bonded in a see-saw-like geometry to one Li(2), one Fe(5), and two equivalent Co(1) atoms.
Li4Fe9CoO20 crystallizes in the monoclinic P2/m space group. There are two inequivalent Li sites. In the first Li site, Li(1) is bonded to one O(5), one O(8), two equivalent O(6), and two equivalent O(7) atoms to form distorted LiO6 octahedra that share  a cornercorner with one Fe(1)O6 octahedra, corners with five equivalent Fe(3)O6 octahedra, edges with two equivalent Li(1)O6 octahedra, edges with two equivalent Fe(2)O6 octahedra, edges with two equivalent Fe(3)O6 octahedra, and edges with two equivalent Fe(4)O6 octahedra. The corner-sharing octahedral tilt angles range from 6-25°. The Li(1)-O(5) bond length is 1.99 Å. The Li(1)-O(8) bond length is 2.39 Å. Both Li(1)-O(6) bond lengths are 2.17 Å. Both Li(1)-O(7) bond lengths are 2.29 Å. In the second Li site, Li(2) is bonded to one O(10), one O(3), two equivalent O(1), and two equivalent O(9) atoms to form LiO6 octahedra that share  a cornercorner with one Fe(2)O6 octahedra, corners with five equivalent Fe(5)O6 octahedra, edges with two equivalent Li(2)O6 octahedra, edges with two equivalent Fe(1)O6 octahedra, edges with two equivalent Fe(5)O6 octahedra, and edges with two equivalent Co(1)O6 octahedra. The corner-sharing octahedral tilt angles range from 9-20°. The Li(2)-O(10) bond length is 2.10 Å. The Li(2)-O(3) bond length is 2.17 Å. Both Li(2)-O(1) bond lengths are 2.16 Å. Both Li(2)-O(9) bond lengths are 2.21 Å. There are five inequivalent Fe sites. In the first Fe site, Fe(1) is bonded to one O(1), one O(5), two equivalent O(2), and two equivalent O(3) atoms to form FeO6 octahedra that share  a cornercorner with one Li(1)O6 octahedra, edges with two equivalent Li(2)O6 octahedra, edges with two equivalent Fe(1)O6 octahedra, edges with two equivalent Fe(2)O6 octahedra, and edges with two equivalent Fe(5)O6 octahedra. The corner-sharing octahedral tilt angles are 25°. The Fe(1)-O(1) bond length is 2.13 Å. The Fe(1)-O(5) bond length is 2.06 Å. Both Fe(1)-O(2) bond lengths are 1.93 Å. Both Fe(1)-O(3) bond lengths are 1.98 Å. In the second Fe site, Fe(2) is bonded to one O(3), one O(7), two equivalent O(4), and two equivalent O(5) atoms to form FeO6 octahedra that share  a cornercorner with one Li(2)O6 octahedra, edges with two equivalent Li(1)O6 octahedra, edges with two equivalent Fe(1)O6 octahedra, edges with two equivalent Fe(2)O6 octahedra, and edges with two equivalent Fe(3)O6 octahedra. The corner-sharing octahedral tilt angles are 20°. The Fe(2)-O(3) bond length is 2.07 Å. The Fe(2)-O(7) bond length is 2.12 Å. Both Fe(2)-O(4) bond lengths are 1.98 Å. Both Fe(2)-O(5) bond lengths are 1.98 Å. In the third Fe site, Fe(3) is bonded to one O(4), one O(8), two equivalent O(6), and two equivalent O(7) atoms to form FeO6 octahedra that share corners with five equivalent Li(1)O6 octahedra, edges with two equivalent Li(1)O6 octahedra, edges with two equivalent Fe(2)O6 octahedra, edges with two equivalent Fe(3)O6 octahedra, and edges with two equivalent Fe(4)O6 octahedra. The corner-sharing octahedral tilt angles range from 6-9°. The Fe(3)-O(4) bond length is 1.89 Å. The Fe(3)-O(8) bond length is 1.90 Å. Both Fe(3)-O(6) bond lengths are 1.99 Å. Both Fe(3)-O(7) bond lengths are 1.94 Å. In the fourth Fe site, Fe(4) is bonded to two equivalent O(6) and four equivalent O(8) atoms to form FeO6 octahedra that share edges with two equivalent Fe(4)O6 octahedra, edges with four equivalent Li(1)O6 octahedra, and edges with four equivalent Fe(3)O6 octahedra. Both Fe(4)-O(6) bond lengths are 2.00 Å. All Fe(4)-O(8) bond lengths are 2.00 Å. In the fifth Fe site, Fe(5) is bonded to one O(10), one O(2), two equivalent O(1), and two equivalent O(9) atoms to form FeO6 octahedra that share corners with five equivalent Li(2)O6 octahedra, edges with two equivalent Li(2)O6 octahedra, edges with two equivalent Fe(1)O6 octahedra, edges with two equivalent Fe(5)O6 octahedra, and edges with two equivalent Co(1)O6 octahedra. The corner-sharing octahedral tilt angles range from 9-16°. The Fe(5)-O(10) bond length is 2.05 Å. The Fe(5)-O(2) bond length is 2.13 Å. Both Fe(5)-O(1) bond lengths are 1.98 Å. Both Fe(5)-O(9) bond lengths are 2.04 Å. Co(1) is bonded to two equivalent O(9) and four equivalent O(10) atoms to form CoO6 octahedra that share edges with two equivalent Co(1)O6 octahedra, edges with four equivalent Li(2)O6 octahedra, and edges with four equivalent Fe(5)O6 octahedra. Both Co(1)-O(9) bond lengths are 1.88 Å. All Co(1)-O(10) bond lengths are 1.91 Å. There are ten inequivalent O sites. In the first O site, O(1) is bonded to two equivalent Li(2), one Fe(1), and two equivalent Fe(5) atoms to form OLi2Fe3 square pyramids that share corners with four equivalent O(9)Li2Fe2Co square pyramids,  a cornercorner with one O(5)LiFe3 trigonal pyramid, edges with two equivalent O(9)Li2Fe2Co square pyramids, edges with two equivalent O(1)Li2Fe3 square pyramids, and edges with two equivalent O(3)LiFe3 trigonal pyramids. In the second O site, O(2) is bonded in a 3-coordinate geometry to one Fe(5) and two equivalent Fe(1) atoms. In the third O site, O(3) is bonded to one Li(2), one Fe(2), and two equivalent Fe(1) atoms to form OLiFe3 trigonal pyramids that share  a cornercorner with one O(7)Li2Fe3 square pyramid, corners with two equivalent O(9)Li2Fe2Co square pyramids, corners with two equivalent O(3)LiFe3 trigonal pyramids, edges with two equivalent O(1)Li2Fe3 square pyramids, and edges with two equivalent O(5)LiFe3 trigonal pyramids. In the fourth O site, O(4) is bonded in a distorted trigonal non-coplanar geometry to one Fe(3) and two equivalent Fe(2) atoms. In the fifth O site, O(5) is bonded to one Li(1), one Fe(1), and two equivalent Fe(2) atoms to form distorted OLiFe3 trigonal pyramids that share  a cornercorner with one O(1)Li2Fe3 square pyramid, corners with two equivalent O(6)Li2Fe3 square pyramids, corners with two equivalent O(5)LiFe3 trigonal pyramids, edges with two equivalent O(7)Li2Fe3 square pyramids, and edges with two equivalent O(3)LiFe3 trigonal pyramids. In the sixth O site, O(6) is bonded to two equivalent Li(1), one Fe(4), and two equivalent Fe(3) atoms to form OLi2Fe3 square pyramids that share  a cornercorner with one O(6)Li2Fe3 square pyramid, corners with four equivalent O(7)Li2Fe3 square pyramids, corners with two equivalent O(5)LiFe3 trigonal pyramids, edges with two equivalent O(6)Li2Fe3 square pyramids, and edges with two equivalent O(7)Li2Fe3 square pyramids. In the seventh O site, O(7) is bonded to two equivalent Li(1), one Fe(2), and two equivalent Fe(3) atoms to form OLi2Fe3 square pyramids that share corners with four equivalent O(6)Li2Fe3 square pyramids,  a cornercorner with one O(3)LiFe3 trigonal pyramid, edges with two equivalent O(6)Li2Fe3 square pyramids, edges with two equivalent O(7)Li2Fe3 square pyramids, and edges with two equivalent O(5)LiFe3 trigonal pyramids. In the eighth O site, O(8) is bonded in a rectangular see-saw-like geometry to one Li(1), one Fe(3), and two equivalent Fe(4) atoms. In the ninth O site, O(9) is bonded to two equivalent Li(2), two equivalent Fe(5), and one Co(1) atom to form OLi2Fe2Co square pyramids that share  a cornercorner with one O(9)Li2Fe2Co square pyramid, corners with four equivalent O(1)Li2Fe3 square pyramids, corners with two equivalent O(3)LiFe3 trigonal pyramids, edges with two equivalent O(9)Li2Fe2Co square pyramids, and edges with two equivalent O(1)Li2Fe3 square pyramids. In the tenth O site, O(10) is bonded in a see-saw-like geometry to one Li(2), one Fe(5), and two equivalent Co(1) atoms.