Li2Nb3MnO8 is Spinel-derived structured and crystallizes in the trigonal R3m space group. There are two inequivalent Li sites. In the first Li site, Li(1) is bonded to one O(1) and three equivalent O(2) atoms to form LiO4 tetrahedra that share corners with three equivalent Li(2)O6 octahedra and corners with nine equivalent Nb(1)O6 octahedra. The corner-sharing octahedral tilt angles range from 51-59°. In the second Li site, Li(2) is bonded to three equivalent O(2) and three equivalent O(3) atoms to form LiO6 octahedra that share corners with three equivalent Li(1)O4 tetrahedra, corners with three equivalent Mn(1)O4 tetrahedra, and edges with six equivalent Nb(1)O6 octahedra. Nb(1) is bonded to one O(1), one O(4), two equivalent O(2), and two equivalent O(3) atoms to form NbO6 octahedra that share corners with three equivalent Li(1)O4 tetrahedra, corners with three equivalent Mn(1)O4 tetrahedra, edges with two equivalent Li(2)O6 octahedra, and edges with four equivalent Nb(1)O6 octahedra. Mn(1) is bonded to one O(4) and three equivalent O(3) atoms to form MnO4 tetrahedra that share corners with three equivalent Li(2)O6 octahedra and corners with nine equivalent Nb(1)O6 octahedra. The corner-sharing octahedral tilt angles range from 59-63°. There are four inequivalent O sites. In the first O site, O(1) is bonded in a rectangular see-saw-like geometry to one Li(1) and three equivalent Nb(1) atoms. In the second O site, O(2) is bonded in a rectangular see-saw-like geometry to one Li(1), one Li(2), and two equivalent Nb(1) atoms. In the third O site, O(3) is bonded to one Li(2), two equivalent Nb(1), and one Mn(1) atom to form distorted OLiMnNb2 trigonal pyramids that share  a cornercorner with one O(4)MnNb3 trigonal pyramid, corners with two equivalent O(3)LiMnNb2 trigonal pyramids,  an edgeedge with one O(4)MnNb3 trigonal pyramid, and edges with two equivalent O(3)LiMnNb2 trigonal pyramids. In the fourth O site, O(4) is bonded to three equivalent Nb(1) and one Mn(1) atom to form a mixture of distorted corner and edge-sharing OMnNb3 trigonal pyramids.
Li2Nb3MnO8 is Spinel-derived structured and crystallizes in the trigonal R3m space group. There are two inequivalent Li sites. In the first Li site, Li(1) is bonded to one O(1) and three equivalent O(2) atoms to form LiO4 tetrahedra that share corners with three equivalent Li(2)O6 octahedra and corners with nine equivalent Nb(1)O6 octahedra. The corner-sharing octahedral tilt angles range from 51-59°. The Li(1)-O(1) bond length is 1.97 Å. All Li(1)-O(2) bond lengths are 1.99 Å. In the second Li site, Li(2) is bonded to three equivalent O(2) and three equivalent O(3) atoms to form LiO6 octahedra that share corners with three equivalent Li(1)O4 tetrahedra, corners with three equivalent Mn(1)O4 tetrahedra, and edges with six equivalent Nb(1)O6 octahedra. All Li(2)-O(2) bond lengths are 2.20 Å. All Li(2)-O(3) bond lengths are 2.15 Å. Nb(1) is bonded to one O(1), one O(4), two equivalent O(2), and two equivalent O(3) atoms to form NbO6 octahedra that share corners with three equivalent Li(1)O4 tetrahedra, corners with three equivalent Mn(1)O4 tetrahedra, edges with two equivalent Li(2)O6 octahedra, and edges with four equivalent Nb(1)O6 octahedra. The Nb(1)-O(1) bond length is 2.13 Å. The Nb(1)-O(4) bond length is 2.19 Å. Both Nb(1)-O(2) bond lengths are 2.05 Å. Both Nb(1)-O(3) bond lengths are 2.09 Å. Mn(1) is bonded to one O(4) and three equivalent O(3) atoms to form MnO4 tetrahedra that share corners with three equivalent Li(2)O6 octahedra and corners with nine equivalent Nb(1)O6 octahedra. The corner-sharing octahedral tilt angles range from 59-63°. The Mn(1)-O(4) bond length is 2.09 Å. All Mn(1)-O(3) bond lengths are 2.08 Å. There are four inequivalent O sites. In the first O site, O(1) is bonded in a rectangular see-saw-like geometry to one Li(1) and three equivalent Nb(1) atoms. In the second O site, O(2) is bonded in a rectangular see-saw-like geometry to one Li(1), one Li(2), and two equivalent Nb(1) atoms. In the third O site, O(3) is bonded to one Li(2), two equivalent Nb(1), and one Mn(1) atom to form distorted OLiMnNb2 trigonal pyramids that share  a cornercorner with one O(4)MnNb3 trigonal pyramid, corners with two equivalent O(3)LiMnNb2 trigonal pyramids,  an edgeedge with one O(4)MnNb3 trigonal pyramid, and edges with two equivalent O(3)LiMnNb2 trigonal pyramids. In the fourth O site, O(4) is bonded to three equivalent Nb(1) and one Mn(1) atom to form a mixture of distorted corner and edge-sharing OMnNb3 trigonal pyramids.