Li2TiMn2NiO8 is Spinel-derived structured and crystallizes in the monoclinic C2/m space group. Li(1) is bonded to one O(1), one O(2), and two equivalent O(3) atoms to form LiO4 tetrahedra that share corners with three equivalent Ti(1)O6 octahedra, corners with three equivalent Ni(1)O6 octahedra, and corners with six equivalent Mn(1)O6 octahedra. The corner-sharing octahedral tilt angles range from 57-63°. Ti(1) is bonded to two equivalent O(1) and four equivalent O(3) atoms to form TiO6 octahedra that share corners with six equivalent Li(1)O4 tetrahedra, edges with two equivalent Ni(1)O6 octahedra, and edges with four equivalent Mn(1)O6 octahedra. Mn(1) is bonded to two equivalent O(1), two equivalent O(2), and two equivalent O(3) atoms to form MnO6 octahedra that share corners with six equivalent Li(1)O4 tetrahedra, edges with two equivalent Ti(1)O6 octahedra, edges with two equivalent Mn(1)O6 octahedra, and edges with two equivalent Ni(1)O6 octahedra. Ni(1) is bonded to two equivalent O(2) and four equivalent O(3) atoms to form NiO6 octahedra that share corners with six equivalent Li(1)O4 tetrahedra, edges with two equivalent Ti(1)O6 octahedra, and edges with four equivalent Mn(1)O6 octahedra. There are three inequivalent O sites. In the first O site, O(1) is bonded to one Li(1), one Ti(1), and two equivalent Mn(1) atoms to form distorted OLiTiMn2 trigonal pyramids that share corners with three equivalent O(2)LiMn2Ni trigonal pyramids, corners with three equivalent O(1)LiTiMn2 trigonal pyramids, and  an edgeedge with one O(2)LiMn2Ni trigonal pyramid. In the second O site, O(2) is bonded to one Li(1), two equivalent Mn(1), and one Ni(1) atom to form distorted OLiMn2Ni trigonal pyramids that share corners with three equivalent O(2)LiMn2Ni trigonal pyramids, corners with three equivalent O(1)LiTiMn2 trigonal pyramids, and  an edgeedge with one O(1)LiTiMn2 trigonal pyramid. In the third O site, O(3) is bonded in a distorted rectangular see-saw-like geometry to one Li(1), one Ti(1), one Mn(1), and one Ni(1) atom.
Li2TiMn2NiO8 is Spinel-derived structured and crystallizes in the monoclinic C2/m space group. Li(1) is bonded to one O(1), one O(2), and two equivalent O(3) atoms to form LiO4 tetrahedra that share corners with three equivalent Ti(1)O6 octahedra, corners with three equivalent Ni(1)O6 octahedra, and corners with six equivalent Mn(1)O6 octahedra. The corner-sharing octahedral tilt angles range from 57-63°. The Li(1)-O(1) bond length is 2.09 Å. The Li(1)-O(2) bond length is 2.01 Å. Both Li(1)-O(3) bond lengths are 1.95 Å. Ti(1) is bonded to two equivalent O(1) and four equivalent O(3) atoms to form TiO6 octahedra that share corners with six equivalent Li(1)O4 tetrahedra, edges with two equivalent Ni(1)O6 octahedra, and edges with four equivalent Mn(1)O6 octahedra. Both Ti(1)-O(1) bond lengths are 2.03 Å. All Ti(1)-O(3) bond lengths are 1.96 Å. Mn(1) is bonded to two equivalent O(1), two equivalent O(2), and two equivalent O(3) atoms to form MnO6 octahedra that share corners with six equivalent Li(1)O4 tetrahedra, edges with two equivalent Ti(1)O6 octahedra, edges with two equivalent Mn(1)O6 octahedra, and edges with two equivalent Ni(1)O6 octahedra. Both Mn(1)-O(1) bond lengths are 1.98 Å. Both Mn(1)-O(2) bond lengths are 1.94 Å. Both Mn(1)-O(3) bond lengths are 1.93 Å. Ni(1) is bonded to two equivalent O(2) and four equivalent O(3) atoms to form NiO6 octahedra that share corners with six equivalent Li(1)O4 tetrahedra, edges with two equivalent Ti(1)O6 octahedra, and edges with four equivalent Mn(1)O6 octahedra. Both Ni(1)-O(2) bond lengths are 2.08 Å. All Ni(1)-O(3) bond lengths are 2.08 Å. There are three inequivalent O sites. In the first O site, O(1) is bonded to one Li(1), one Ti(1), and two equivalent Mn(1) atoms to form distorted OLiTiMn2 trigonal pyramids that share corners with three equivalent O(2)LiMn2Ni trigonal pyramids, corners with three equivalent O(1)LiTiMn2 trigonal pyramids, and  an edgeedge with one O(2)LiMn2Ni trigonal pyramid. In the second O site, O(2) is bonded to one Li(1), two equivalent Mn(1), and one Ni(1) atom to form distorted OLiMn2Ni trigonal pyramids that share corners with three equivalent O(2)LiMn2Ni trigonal pyramids, corners with three equivalent O(1)LiTiMn2 trigonal pyramids, and  an edgeedge with one O(1)LiTiMn2 trigonal pyramid. In the third O site, O(3) is bonded in a distorted rectangular see-saw-like geometry to one Li(1), one Ti(1), one Mn(1), and one Ni(1) atom.