Li3(FeO2)4 crystallizes in the monoclinic C2/m space group. There are two inequivalent Li sites. In the first Li site, Li(1) is bonded to two equivalent O(1), two equivalent O(2), and two equivalent O(4) atoms to form LiO6 octahedra that share corners with six equivalent Fe(3)O6 octahedra, edges with two equivalent Fe(2)O6 octahedra, edges with four equivalent Li(2)O6 octahedra, and edges with four equivalent Fe(1)O6 octahedra. The corner-sharing octahedral tilt angles range from 0-13°. In the second Li site, Li(2) is bonded to two equivalent O(1), two equivalent O(3), and two equivalent O(4) atoms to form LiO6 octahedra that share corners with six equivalent Li(2)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 four equivalent Fe(1)O6 octahedra. The corner-sharing octahedral tilt angles range from 3-12°. There are three inequivalent Fe sites. In the first Fe site, Fe(1) is bonded to two equivalent O(1), two equivalent O(2), and two equivalent O(3) atoms to form FeO6 octahedra that share corners with six equivalent Fe(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 four equivalent Li(2)O6 octahedra. The corner-sharing octahedral tilt angles range from 3-9°. In the second Fe site, Fe(2) is bonded to two equivalent O(2), two equivalent O(3), and two equivalent O(4) atoms to form FeO6 octahedra that share edges with two equivalent Li(1)O6 octahedra, edges with two equivalent Fe(3)O6 octahedra, edges with four equivalent Li(2)O6 octahedra, and edges with four equivalent Fe(1)O6 octahedra. In the third Fe site, Fe(3) is bonded to two equivalent O(1), two equivalent O(2), and two equivalent O(4) atoms to form FeO6 octahedra that share corners with six equivalent Li(1)O6 octahedra, edges with two equivalent Fe(2)O6 octahedra, edges with four equivalent Li(2)O6 octahedra, and edges with four equivalent Fe(1)O6 octahedra. The corner-sharing octahedral tilt angles range from 0-13°. There are four inequivalent O sites. In the first O site, O(1) is bonded to one Li(1), two equivalent Li(2), one Fe(3), and two equivalent Fe(1) atoms to form OLi3Fe3 octahedra that share corners with six equivalent O(1)Li3Fe3 octahedra, edges with four equivalent O(3)Li2Fe3 square pyramids, edges with four equivalent O(4)Li3Fe2 square pyramids, and edges with four equivalent O(2)LiFe4 square pyramids. The corner-sharing octahedra are not tilted. In the second O site, O(2) is bonded to one Li(1), one Fe(2), one Fe(3), and two equivalent Fe(1) atoms to form OLiFe4 square pyramids that share corners with two equivalent O(3)Li2Fe3 square pyramids, corners with two equivalent O(4)Li3Fe2 square pyramids, corners with five equivalent O(2)LiFe4 square pyramids, edges with four equivalent O(1)Li3Fe3 octahedra, edges with two equivalent O(3)Li2Fe3 square pyramids, and edges with two equivalent O(4)Li3Fe2 square pyramids. In the third O site, O(3) is bonded to two equivalent Li(2), one Fe(2), and two equivalent Fe(1) atoms to form OLi2Fe3 square pyramids that share corners with two equivalent O(4)Li3Fe2 square pyramids, corners with two equivalent O(2)LiFe4 square pyramids, corners with five equivalent O(3)Li2Fe3 square pyramids, edges with four equivalent O(1)Li3Fe3 octahedra, edges with two equivalent O(4)Li3Fe2 square pyramids, and edges with two equivalent O(2)LiFe4 square pyramids. In the fourth O site, O(4) is bonded to one Li(1), two equivalent Li(2), one Fe(2), and one Fe(3) atom to form OLi3Fe2 square pyramids that share corners with two equivalent O(3)Li2Fe3 square pyramids, corners with two equivalent O(2)LiFe4 square pyramids, corners with five equivalent O(4)Li3Fe2 square pyramids, edges with four equivalent O(1)Li3Fe3 octahedra, edges with two equivalent O(3)Li2Fe3 square pyramids, and edges with two equivalent O(2)LiFe4 square pyramids.
Li3(FeO2)4 crystallizes in the monoclinic C2/m space group. There are two inequivalent Li sites. In the first Li site, Li(1) is bonded to two equivalent O(1), two equivalent O(2), and two equivalent O(4) atoms to form LiO6 octahedra that share corners with six equivalent Fe(3)O6 octahedra, edges with two equivalent Fe(2)O6 octahedra, edges with four equivalent Li(2)O6 octahedra, and edges with four equivalent Fe(1)O6 octahedra. The corner-sharing octahedral tilt angles range from 0-13°. Both Li(1)-O(1) bond lengths are 2.17 Å. Both Li(1)-O(2) bond lengths are 2.10 Å. Both Li(1)-O(4) bond lengths are 2.10 Å. In the second Li site, Li(2) is bonded to two equivalent O(1), two equivalent O(3), and two equivalent O(4) atoms to form LiO6 octahedra that share corners with six equivalent Li(2)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 four equivalent Fe(1)O6 octahedra. The corner-sharing octahedral tilt angles range from 3-12°. Both Li(2)-O(1) bond lengths are 2.04 Å. Both Li(2)-O(3) bond lengths are 2.09 Å. Both Li(2)-O(4) bond lengths are 2.13 Å. There are three inequivalent Fe sites. In the first Fe site, Fe(1) is bonded to two equivalent O(1), two equivalent O(2), and two equivalent O(3) atoms to form FeO6 octahedra that share corners with six equivalent Fe(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 four equivalent Li(2)O6 octahedra. The corner-sharing octahedral tilt angles range from 3-9°. Both Fe(1)-O(1) bond lengths are 2.08 Å. Both Fe(1)-O(2) bond lengths are 2.12 Å. Both Fe(1)-O(3) bond lengths are 2.04 Å. In the second Fe site, Fe(2) is bonded to two equivalent O(2), two equivalent O(3), and two equivalent O(4) atoms to form FeO6 octahedra that share edges with two equivalent Li(1)O6 octahedra, edges with two equivalent Fe(3)O6 octahedra, edges with four equivalent Li(2)O6 octahedra, and edges with four equivalent Fe(1)O6 octahedra. Both Fe(2)-O(2) bond lengths are 1.94 Å. Both Fe(2)-O(3) bond lengths are 1.97 Å. Both Fe(2)-O(4) bond lengths are 1.86 Å. In the third Fe site, Fe(3) is bonded to two equivalent O(1), two equivalent O(2), and two equivalent O(4) atoms to form FeO6 octahedra that share corners with six equivalent Li(1)O6 octahedra, edges with two equivalent Fe(2)O6 octahedra, edges with four equivalent Li(2)O6 octahedra, and edges with four equivalent Fe(1)O6 octahedra. The corner-sharing octahedral tilt angles range from 0-13°. Both Fe(3)-O(1) bond lengths are 2.07 Å. Both Fe(3)-O(2) bond lengths are 2.08 Å. Both Fe(3)-O(4) bond lengths are 1.99 Å. There are four inequivalent O sites. In the first O site, O(1) is bonded to one Li(1), two equivalent Li(2), one Fe(3), and two equivalent Fe(1) atoms to form OLi3Fe3 octahedra that share corners with six equivalent O(1)Li3Fe3 octahedra, edges with four equivalent O(3)Li2Fe3 square pyramids, edges with four equivalent O(4)Li3Fe2 square pyramids, and edges with four equivalent O(2)LiFe4 square pyramids. The corner-sharing octahedra are not tilted. In the second O site, O(2) is bonded to one Li(1), one Fe(2), one Fe(3), and two equivalent Fe(1) atoms to form OLiFe4 square pyramids that share corners with two equivalent O(3)Li2Fe3 square pyramids, corners with two equivalent O(4)Li3Fe2 square pyramids, corners with five equivalent O(2)LiFe4 square pyramids, edges with four equivalent O(1)Li3Fe3 octahedra, edges with two equivalent O(3)Li2Fe3 square pyramids, and edges with two equivalent O(4)Li3Fe2 square pyramids. In the third O site, O(3) is bonded to two equivalent Li(2), one Fe(2), and two equivalent Fe(1) atoms to form OLi2Fe3 square pyramids that share corners with two equivalent O(4)Li3Fe2 square pyramids, corners with two equivalent O(2)LiFe4 square pyramids, corners with five equivalent O(3)Li2Fe3 square pyramids, edges with four equivalent O(1)Li3Fe3 octahedra, edges with two equivalent O(4)Li3Fe2 square pyramids, and edges with two equivalent O(2)LiFe4 square pyramids. In the fourth O site, O(4) is bonded to one Li(1), two equivalent Li(2), one Fe(2), and one Fe(3) atom to form OLi3Fe2 square pyramids that share corners with two equivalent O(3)Li2Fe3 square pyramids, corners with two equivalent O(2)LiFe4 square pyramids, corners with five equivalent O(4)Li3Fe2 square pyramids, edges with four equivalent O(1)Li3Fe3 octahedra, edges with two equivalent O(3)Li2Fe3 square pyramids, and edges with two equivalent O(2)LiFe4 square pyramids.