Li4Fe3(NiO4)3 crystallizes in the orthorhombic F222 space group. There are two inequivalent Li sites. In the first Li site, Li(1) is bonded to two equivalent O(2), two equivalent O(3), and two equivalent O(4) atoms to form distorted LiO6 octahedra that share corners with two equivalent Li(1)O6 octahedra, corners with two equivalent Ni(2)O6 octahedra,  an edgeedge with one Ni(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 three equivalent Ni(2)O6 octahedra. The corner-sharing octahedral tilt angles range from 5-17°. In the second Li site, Li(2) is bonded to two equivalent O(1), two equivalent O(2), and two equivalent O(3) atoms to form distorted LiO6 octahedra that share corners with two equivalent Li(2)O6 octahedra, corners with two equivalent Fe(1)O6 octahedra,  an edgeedge with one Fe(2)O6 octahedra, edges with two equivalent Li(1)O6 octahedra, edges with two equivalent Ni(1)O6 octahedra, edges with two equivalent Ni(2)O6 octahedra, and edges with three equivalent Fe(1)O6 octahedra. The corner-sharing octahedral tilt angles range from 4-17°. There are two 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 two equivalent Li(2)O6 octahedra, corners with two equivalent Fe(1)O6 octahedra, corners with two equivalent Fe(2)O6 octahedra, edges with two equivalent Li(1)O6 octahedra, edges with two equivalent Ni(1)O6 octahedra, edges with two equivalent Ni(2)O6 octahedra, and edges with three equivalent Li(2)O6 octahedra. The corner-sharing octahedral tilt angles range from 4-16°. In the second Fe site, Fe(2) is bonded to two equivalent O(4) and four equivalent O(2) atoms to form FeO6 octahedra that share corners with four equivalent Fe(1)O6 octahedra, edges with two equivalent Li(2)O6 octahedra, edges with four equivalent Li(1)O6 octahedra, and edges with four equivalent Ni(2)O6 octahedra. The corner-sharing octahedral tilt angles are 15°. There are two inequivalent Ni sites. In the first Ni site, Ni(1) is bonded to two equivalent O(1) and four equivalent O(3) atoms to form NiO6 octahedra that share corners with four equivalent Ni(2)O6 octahedra, edges with two equivalent Li(1)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 are 16°. In the second Ni site, Ni(2) is bonded to two equivalent O(2), two equivalent O(3), and two equivalent O(4) atoms to form NiO6 octahedra that share corners with two equivalent Li(1)O6 octahedra, corners with two equivalent Ni(1)O6 octahedra, corners with two equivalent Ni(2)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 three equivalent Li(1)O6 octahedra. The corner-sharing octahedral tilt angles range from 5-16°. There are four inequivalent O sites. In the first O site, O(1) is bonded to two equivalent Li(2), two equivalent Fe(1), and one Ni(1) atom to form OLi2Fe2Ni square pyramids that share  a cornercorner with one O(1)Li2Fe2Ni square pyramid, corners with four equivalent O(2)Li2Fe2Ni square pyramids, corners with four equivalent O(3)Li2FeNi2 square pyramids, edges with two equivalent O(1)Li2Fe2Ni square pyramids, edges with two equivalent O(2)Li2Fe2Ni square pyramids, and edges with four equivalent O(3)Li2FeNi2 square pyramids. In the second O site, O(2) is bonded to one Li(1), one Li(2), one Fe(1), one Fe(2), and one Ni(2) atom to form OLi2Fe2Ni square pyramids that share corners with two equivalent O(1)Li2Fe2Ni square pyramids, corners with two equivalent O(4)Li2FeNi2 square pyramids, corners with five equivalent O(2)Li2Fe2Ni square pyramids,  an edgeedge with one O(1)Li2Fe2Ni square pyramid,  an edgeedge with one O(2)Li2Fe2Ni square pyramid, edges with two equivalent O(4)Li2FeNi2 square pyramids, and edges with four equivalent O(3)Li2FeNi2 square pyramids. In the third O site, O(3) is bonded to one Li(1), one Li(2), one Fe(1), one Ni(1), and one Ni(2) atom to form distorted OLi2FeNi2 square pyramids that share corners with two equivalent O(1)Li2Fe2Ni square pyramids, corners with two equivalent O(4)Li2FeNi2 square pyramids, corners with five equivalent O(3)Li2FeNi2 square pyramids,  an edgeedge with one O(3)Li2FeNi2 square pyramid,  an edgeedge with one O(4)Li2FeNi2 square pyramid, edges with two equivalent O(1)Li2Fe2Ni square pyramids, and edges with four equivalent O(2)Li2Fe2Ni square pyramids. In the fourth O site, O(4) is bonded to two equivalent Li(1), one Fe(2), and two equivalent Ni(2) atoms to form OLi2FeNi2 square pyramids that share  a cornercorner with one O(4)Li2FeNi2 square pyramid, corners with four equivalent O(2)Li2Fe2Ni square pyramids, corners with four equivalent O(3)Li2FeNi2 square pyramids, edges with two equivalent O(3)Li2FeNi2 square pyramids, edges with two equivalent O(4)Li2FeNi2 square pyramids, and edges with four equivalent O(2)Li2Fe2Ni square pyramids.
Li4Fe3(NiO4)3 crystallizes in the orthorhombic F222 space group. There are two inequivalent Li sites. In the first Li site, Li(1) is bonded to two equivalent O(2), two equivalent O(3), and two equivalent O(4) atoms to form distorted LiO6 octahedra that share corners with two equivalent Li(1)O6 octahedra, corners with two equivalent Ni(2)O6 octahedra,  an edgeedge with one Ni(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 three equivalent Ni(2)O6 octahedra. The corner-sharing octahedral tilt angles range from 5-17°. Both Li(1)-O(2) bond lengths are 2.43 Å. Both Li(1)-O(3) bond lengths are 1.99 Å. Both Li(1)-O(4) bond lengths are 1.99 Å. In the second Li site, Li(2) is bonded to two equivalent O(1), two equivalent O(2), and two equivalent O(3) atoms to form distorted LiO6 octahedra that share corners with two equivalent Li(2)O6 octahedra, corners with two equivalent Fe(1)O6 octahedra,  an edgeedge with one Fe(2)O6 octahedra, edges with two equivalent Li(1)O6 octahedra, edges with two equivalent Ni(1)O6 octahedra, edges with two equivalent Ni(2)O6 octahedra, and edges with three equivalent Fe(1)O6 octahedra. The corner-sharing octahedral tilt angles range from 4-17°. Both Li(2)-O(1) bond lengths are 1.99 Å. Both Li(2)-O(2) bond lengths are 1.99 Å. Both Li(2)-O(3) bond lengths are 2.46 Å. There are two 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 two equivalent Li(2)O6 octahedra, corners with two equivalent Fe(1)O6 octahedra, corners with two equivalent Fe(2)O6 octahedra, edges with two equivalent Li(1)O6 octahedra, edges with two equivalent Ni(1)O6 octahedra, edges with two equivalent Ni(2)O6 octahedra, and edges with three equivalent Li(2)O6 octahedra. The corner-sharing octahedral tilt angles range from 4-16°. Both Fe(1)-O(1) bond lengths are 2.07 Å. Both Fe(1)-O(2) bond lengths are 2.00 Å. Both Fe(1)-O(3) bond lengths are 1.93 Å. In the second Fe site, Fe(2) is bonded to two equivalent O(4) and four equivalent O(2) atoms to form FeO6 octahedra that share corners with four equivalent Fe(1)O6 octahedra, edges with two equivalent Li(2)O6 octahedra, edges with four equivalent Li(1)O6 octahedra, and edges with four equivalent Ni(2)O6 octahedra. The corner-sharing octahedral tilt angles are 15°. Both Fe(2)-O(4) bond lengths are 1.90 Å. All Fe(2)-O(2) bond lengths are 2.03 Å. There are two inequivalent Ni sites. In the first Ni site, Ni(1) is bonded to two equivalent O(1) and four equivalent O(3) atoms to form NiO6 octahedra that share corners with four equivalent Ni(2)O6 octahedra, edges with two equivalent Li(1)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 are 16°. Both Ni(1)-O(1) bond lengths are 1.90 Å. All Ni(1)-O(3) bond lengths are 2.03 Å. In the second Ni site, Ni(2) is bonded to two equivalent O(2), two equivalent O(3), and two equivalent O(4) atoms to form NiO6 octahedra that share corners with two equivalent Li(1)O6 octahedra, corners with two equivalent Ni(1)O6 octahedra, corners with two equivalent Ni(2)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 three equivalent Li(1)O6 octahedra. The corner-sharing octahedral tilt angles range from 5-16°. Both Ni(2)-O(2) bond lengths are 1.95 Å. Both Ni(2)-O(3) bond lengths are 2.01 Å. Both Ni(2)-O(4) bond lengths are 2.06 Å. There are four inequivalent O sites. In the first O site, O(1) is bonded to two equivalent Li(2), two equivalent Fe(1), and one Ni(1) atom to form OLi2Fe2Ni square pyramids that share  a cornercorner with one O(1)Li2Fe2Ni square pyramid, corners with four equivalent O(2)Li2Fe2Ni square pyramids, corners with four equivalent O(3)Li2FeNi2 square pyramids, edges with two equivalent O(1)Li2Fe2Ni square pyramids, edges with two equivalent O(2)Li2Fe2Ni square pyramids, and edges with four equivalent O(3)Li2FeNi2 square pyramids. In the second O site, O(2) is bonded to one Li(1), one Li(2), one Fe(1), one Fe(2), and one Ni(2) atom to form OLi2Fe2Ni square pyramids that share corners with two equivalent O(1)Li2Fe2Ni square pyramids, corners with two equivalent O(4)Li2FeNi2 square pyramids, corners with five equivalent O(2)Li2Fe2Ni square pyramids,  an edgeedge with one O(1)Li2Fe2Ni square pyramid,  an edgeedge with one O(2)Li2Fe2Ni square pyramid, edges with two equivalent O(4)Li2FeNi2 square pyramids, and edges with four equivalent O(3)Li2FeNi2 square pyramids. In the third O site, O(3) is bonded to one Li(1), one Li(2), one Fe(1), one Ni(1), and one Ni(2) atom to form distorted OLi2FeNi2 square pyramids that share corners with two equivalent O(1)Li2Fe2Ni square pyramids, corners with two equivalent O(4)Li2FeNi2 square pyramids, corners with five equivalent O(3)Li2FeNi2 square pyramids,  an edgeedge with one O(3)Li2FeNi2 square pyramid,  an edgeedge with one O(4)Li2FeNi2 square pyramid, edges with two equivalent O(1)Li2Fe2Ni square pyramids, and edges with four equivalent O(2)Li2Fe2Ni square pyramids. In the fourth O site, O(4) is bonded to two equivalent Li(1), one Fe(2), and two equivalent Ni(2) atoms to form OLi2FeNi2 square pyramids that share  a cornercorner with one O(4)Li2FeNi2 square pyramid, corners with four equivalent O(2)Li2Fe2Ni square pyramids, corners with four equivalent O(3)Li2FeNi2 square pyramids, edges with two equivalent O(3)Li2FeNi2 square pyramids, edges with two equivalent O(4)Li2FeNi2 square pyramids, and edges with four equivalent O(2)Li2Fe2Ni square pyramids.