Materials Data on Li6Cr2O7 by Materials Project
Li6Cr2O7 crystallizes in the monoclinic P2_1/c space group. The structure is three-dimensional. there are three inequivalent Li1+ sites. In the first Li1+ site, Li1+ is bonded to five O2- atoms to form LiO5 trigonal bipyramids that share corners with six LiO5 square pyramids, corners with three equivalent LiO5 trigonal bipyramids, edges with four equivalent CrO6 octahedra, and edges with four LiO5 square pyramids. There are a spread of Li–O bond distances ranging from 1.95–2.08 Å. In the second Li1+ site, Li1+ is bonded to five O2- atoms to form LiO5 square pyramids that share corners with five LiO5 square pyramids, corners with four equivalent LiO5 trigonal bipyramids, edges with four equivalent CrO6 octahedra, edges with two equivalent LiO5 square pyramids, and edges with two equivalent LiO5 trigonal bipyramids. There are a spread of Li–O bond distances ranging from 1.99–2.04 Å. In the third Li1+ site, Li1+ is bonded to five O2- atoms to form distorted LiO5 square pyramids that share corners with three equivalent CrO6 octahedra, corners with four LiO5 square pyramids, corners with two equivalent LiO5 trigonal bipyramids, edges with three equivalent CrO6 octahedra, edges with three LiO5 square pyramids, and edges with two equivalent LiO5 trigonal bipyramids. The corner-sharing octahedra tilt angles range from 5–16°. There are a spread of Li–O bond distances ranging from 1.96–2.27 Å. Cr4+ is bonded to six O2- atoms to form CrO6 octahedra that share corners with three equivalent CrO6 octahedra, corners with three equivalent LiO5 square pyramids, an edgeedge with one CrO6 octahedra, edges with seven LiO5 square pyramids, and edges with four equivalent LiO5 trigonal bipyramids. The corner-sharing octahedra tilt angles range from 0–7°. There are a spread of Cr–O bond distances ranging from 1.83–2.07 Å. There are four inequivalent O2- sites. In the first O2- site, O2- is bonded to four Li1+ and two equivalent Cr4+ atoms to form OLi4Cr2 octahedra that share corners with six equivalent OLi5Cr octahedra and edges with ten OLi4Cr2 octahedra. The corner-sharing octahedra tilt angles range from 2–17°. In the second O2- site, O2- is bonded to four Li1+ and two equivalent Cr4+ atoms to form a mixture of edge and corner-sharing OLi4Cr2 octahedra. The corner-sharing octahedra tilt angles range from 4–20°. In the third O2- site, O2- is bonded to five Li1+ and one Cr4+ atom to form a mixture of edge and corner-sharing OLi5Cr octahedra. The corner-sharing octahedra tilt angles range from 2–17°. In the fourth O2- site, O2- is bonded to four Li1+ and two equivalent Cr4+ atoms to form a mixture of edge and corner-sharing OLi4Cr2 octahedra. The corner-sharing octahedra tilt angles range from 4–20°.