Li4Mn5FeO12 crystallizes in the monoclinic C2/m space group. Li(1) is bonded in a distorted rectangular see-saw-like geometry to two equivalent O(1) and two equivalent O(2) atoms. There are three inequivalent Mn sites. In the first Mn site, Mn(1) is bonded to two equivalent O(3) and four equivalent O(2) atoms to form edge-sharing MnO6 octahedra. In the second Mn site, Mn(2) is bonded to two equivalent O(4) and four equivalent O(1) atoms to form MnO6 octahedra that share edges with three equivalent Mn(2)O6 octahedra and edges with three equivalent Fe(1)O6 octahedra. In the third Mn site, Mn(3) is bonded to two equivalent O(3) and four equivalent O(2) atoms to form edge-sharing MnO6 octahedra. Fe(1) is bonded to two equivalent O(4) and four equivalent O(1) atoms to form FeO6 octahedra that share edges with six equivalent Mn(2)O6 octahedra. There are four inequivalent O sites. In the first O site, O(1) is bonded to two equivalent Li(1), two equivalent Mn(2), and one Fe(1) atom to form distorted OLi2Mn2Fe trigonal bipyramids that share corners with two equivalent O(2)Li2Mn3 trigonal bipyramids, corners with three equivalent O(1)Li2Mn2Fe trigonal bipyramids,  an edgeedge with one O(2)Li2Mn3 trigonal bipyramid, and edges with four equivalent O(1)Li2Mn2Fe trigonal bipyramids. In the second O site, O(2) is bonded to two equivalent Li(1), one Mn(3), and two equivalent Mn(1) atoms to form distorted OLi2Mn3 trigonal bipyramids that share corners with two equivalent O(1)Li2Mn2Fe trigonal bipyramids, corners with three equivalent O(2)Li2Mn3 trigonal bipyramids,  an edgeedge with one O(1)Li2Mn2Fe trigonal bipyramid, and edges with four equivalent O(2)Li2Mn3 trigonal bipyramids. In the third O site, O(3) is bonded in a distorted trigonal non-coplanar geometry to one Mn(3) and two equivalent Mn(1) atoms. In the fourth O site, O(4) is bonded in a distorted T-shaped geometry to two equivalent Mn(2) and one Fe(1) atom.
Li4Mn5FeO12 crystallizes in the monoclinic C2/m space group. Li(1) is bonded in a distorted rectangular see-saw-like geometry to two equivalent O(1) and two equivalent O(2) atoms. There is one shorter (2.05 Å) and one longer (2.07 Å) Li(1)-O(1) bond length. There is one shorter (2.04 Å) and one longer (2.08 Å) Li(1)-O(2) bond length. There are three inequivalent Mn sites. In the first Mn site, Mn(1) is bonded to two equivalent O(3) and four equivalent O(2) atoms to form edge-sharing MnO6 octahedra. Both Mn(1)-O(3) bond lengths are 1.96 Å. There are two shorter (1.95 Å) and two longer (2.09 Å) Mn(1)-O(2) bond lengths. In the second Mn site, Mn(2) is bonded to two equivalent O(4) and four equivalent O(1) atoms to form MnO6 octahedra that share edges with three equivalent Mn(2)O6 octahedra and edges with three equivalent Fe(1)O6 octahedra. Both Mn(2)-O(4) bond lengths are 1.95 Å. There are two shorter (1.97 Å) and two longer (2.10 Å) Mn(2)-O(1) bond lengths. In the third Mn site, Mn(3) is bonded to two equivalent O(3) and four equivalent O(2) atoms to form edge-sharing MnO6 octahedra. Both Mn(3)-O(3) bond lengths are 1.94 Å. All Mn(3)-O(2) bond lengths are 2.13 Å. Fe(1) is bonded to two equivalent O(4) and four equivalent O(1) atoms to form FeO6 octahedra that share edges with six equivalent Mn(2)O6 octahedra. Both Fe(1)-O(4) bond lengths are 2.01 Å. All Fe(1)-O(1) bond lengths are 2.08 Å. There are four inequivalent O sites. In the first O site, O(1) is bonded to two equivalent Li(1), two equivalent Mn(2), and one Fe(1) atom to form distorted OLi2Mn2Fe trigonal bipyramids that share corners with two equivalent O(2)Li2Mn3 trigonal bipyramids, corners with three equivalent O(1)Li2Mn2Fe trigonal bipyramids,  an edgeedge with one O(2)Li2Mn3 trigonal bipyramid, and edges with four equivalent O(1)Li2Mn2Fe trigonal bipyramids. In the second O site, O(2) is bonded to two equivalent Li(1), one Mn(3), and two equivalent Mn(1) atoms to form distorted OLi2Mn3 trigonal bipyramids that share corners with two equivalent O(1)Li2Mn2Fe trigonal bipyramids, corners with three equivalent O(2)Li2Mn3 trigonal bipyramids,  an edgeedge with one O(1)Li2Mn2Fe trigonal bipyramid, and edges with four equivalent O(2)Li2Mn3 trigonal bipyramids. In the third O site, O(3) is bonded in a distorted trigonal non-coplanar geometry to one Mn(3) and two equivalent Mn(1) atoms. In the fourth O site, O(4) is bonded in a distorted T-shaped geometry to two equivalent Mn(2) and one Fe(1) atom.