DOI: 10.17188/1300049
title: Materials Data on Li9Al(CoO4)2 by Materials Project

description: Li9Al(CoO4)2 crystallizes in the orthorhombic Pnma space group. The structure is three-dimensional. there are six inequivalent Li1+ sites. In the first Li1+ site, Li1+ is bonded to four O2- atoms to form LiO4 tetrahedra that share corners with two CoO4 tetrahedra, corners with two equivalent AlO4 tetrahedra, corners with seven LiO4 tetrahedra, an edgeedge with one CoO4 tetrahedra, and edges with two LiO4 tetrahedra. There are a spread of Li–O bond distances ranging from 1.89–2.01 Å. In the second Li1+ site, Li1+ is bonded in a 3-coordinate geometry to five O2- atoms. There are a spread of Li–O bond distances ranging from 1.93–2.40 Å. In the third Li1+ site, Li1+ is bonded to four O2- atoms to form distorted LiO4 tetrahedra that share a cornercorner with one AlO4 tetrahedra, corners with four CoO4 tetrahedra, corners with eight LiO4 tetrahedra, and an edgeedge with one AlO4 tetrahedra. There are a spread of Li–O bond distances ranging from 1.90–2.13 Å. In the fourth Li1+ site, Li1+ is bonded in a trigonal non-coplanar geometry to three O2- atoms. There is one shorter (1.83 Å) and two longer (1.93 Å) Li–O bond length. In the fifth Li1+ site, Li1+ is bonded to four O2- atoms to form distorted LiO4 tetrahedra that share a cornercorner with one AlO4 tetrahedra, corners with two equivalent CoO4 tetrahedra, corners with eight LiO4 tetrahedra, an edgeedge with one CoO4 tetrahedra, and edges with two equivalent LiO4 tetrahedra. There are a spread of Li–O bond distances ranging from 1.92–2.33 Å. In the sixth Li1+ site, Li1+ is bonded to four O2- atoms to form distorted LiO4 tetrahedra that share corners with two CoO4 tetrahedra, corners with nine LiO4 tetrahedra, an edgeedge with one CoO4 tetrahedra, and edges with two LiO4 tetrahedra. There are a spread of Li–O bond distances ranging from 2.00–2.07 Å. There are two inequivalent Co2+ sites. In the first Co2+ site, Co2+ is bonded to four O2- atoms to form CoO4 tetrahedra that share corners with three equivalent AlO4 tetrahedra, corners with eight LiO4 tetrahedra, and edges with three LiO4 tetrahedra. There are a spread of Co–O bond distances ranging from 1.97–2.04 Å. In the second Co2+ site, Co2+ is bonded to four O2- atoms to form CoO4 tetrahedra that share a cornercorner with one AlO4 tetrahedra, corners with ten LiO4 tetrahedra, and edges with two equivalent LiO4 tetrahedra. There are a spread of Co–O bond distances ranging from 1.95–2.02 Å. Al3+ is bonded to four O2- atoms to form AlO4 tetrahedra that share corners with four CoO4 tetrahedra, corners with seven LiO4 tetrahedra, and edges with two equivalent LiO4 tetrahedra. There are a spread of Al–O bond distances ranging from 1.78–1.83 Å. There are six inequivalent O2- sites. In the first O2- site, O2- is bonded in a 5-coordinate geometry to four Li1+, one Co2+, and one Al3+ atom. In the second O2- site, O2- is bonded to three Li1+, one Co2+, and one Al3+ atom to form distorted OLi3AlCo trigonal bipyramids that share corners with four equivalent OLi6Co pentagonal bipyramids and corners with three equivalent OLi2AlCo tetrahedra. In the third O2- site, O2- is bonded in a 7-coordinate geometry to six Li1+ and one Co2+ atom. In the fourth O2- site, O2- is bonded to five Li1+ and one Co2+ atom to form distorted OLi5Co octahedra that share a cornercorner with one OLi2AlCo tetrahedra and edges with four equivalent OLi6Co pentagonal bipyramids. In the fifth O2- site, O2- is bonded to two equivalent Li1+, one Co2+, and one Al3+ atom to form OLi2AlCo tetrahedra that share a cornercorner with one OLi5Co octahedra, corners with four equivalent OLi6Co pentagonal bipyramids, and corners with three equivalent OLi3AlCo trigonal bipyramids. The corner-sharing octahedral tilt angles are 79°. In the sixth O2- site, O2- is bonded to six Li1+ and one Co2+ atom to form distorted OLi6Co pentagonal bipyramids that share corners with two equivalent OLi6Co pentagonal bipyramids, corners with two equivalent OLi2AlCo tetrahedra, corners with two equivalent OLi3AlCo trigonal bipyramids, edges with two equivalent OLi5Co octahedra, and edges with two equivalent OLi6Co pentagonal bipyramids.