Materials Data on LiMn7O12 by Materials Project
LiMn7O12 is Hausmannite-derived structured and crystallizes in the tetragonal I4_1/acd space group. The structure is three-dimensional. Li1+ is bonded to four equivalent O2- atoms to form LiO4 tetrahedra that share corners with twelve MnO6 octahedra. The corner-sharing octahedra tilt angles range from 58–69°. All Li–O bond lengths are 1.91 Å. There are four inequivalent Mn+3.29+ sites. In the first Mn+3.29+ site, Mn+3.29+ is bonded to six O2- atoms to form distorted MnO6 octahedra that share corners with four MnO6 octahedra, corners with two equivalent LiO4 tetrahedra, and edges with four MnO6 octahedra. The corner-sharing octahedra tilt angles range from 44–58°. There are a spread of Mn–O bond distances ranging from 1.87–2.31 Å. In the second Mn+3.29+ site, Mn+3.29+ is bonded to six O2- atoms to form MnO6 octahedra that share corners with four MnO6 octahedra, corners with two equivalent LiO4 tetrahedra, and edges with four MnO6 octahedra. The corner-sharing octahedra tilt angles range from 44–55°. There are a spread of Mn–O bond distances ranging from 1.93–2.01 Å. In the third Mn+3.29+ site, Mn+3.29+ is bonded to six O2- atoms to form distorted MnO6 octahedra that share corners with four MnO6 octahedra, corners with two equivalent LiO4 tetrahedra, and edges with four MnO6 octahedra. The corner-sharing octahedra tilt angles range from 55–58°. There are a spread of Mn–O bond distances ranging from 1.99–2.18 Å. In the fourth Mn+3.29+ site, Mn+3.29+ is bonded in a 8-coordinate geometry to eight O2- atoms. There are four shorter (2.07 Å) and four longer (2.55 Å) Mn–O bond lengths. There are three inequivalent O2- sites. In the first O2- site, O2- is bonded to one Li1+ and three Mn+3.29+ atoms to form distorted OLiMn3 tetrahedra that share corners with ten OLiMn3 tetrahedra and an edgeedge with one OMn4 tetrahedra. In the second O2- site, O2- is bonded in a 3-coordinate geometry to four Mn+3.29+ atoms. In the third O2- site, O2- is bonded to four Mn+3.29+ atoms to form a mixture of distorted edge and corner-sharing OMn4 tetrahedra.