DOI: 10.17188/1300140
title: Materials Data on Li2Cr2O7 by Materials Project

description: Li2Cr2O7 crystallizes in the triclinic P-1 space group. The structure is three-dimensional. there are four inequivalent Li1+ sites. In the first Li1+ site, Li1+ is bonded to six O2- atoms to form distorted LiO6 octahedra that share a cornercorner with one LiO6 octahedra, corners with six CrO4 tetrahedra, and an edgeedge with one LiO6 octahedra. The corner-sharing octahedral tilt angles are 76°. There are a spread of Li–O bond distances ranging from 2.07–2.48 Å. In the second Li1+ site, Li1+ is bonded to six O2- atoms to form distorted LiO6 octahedra that share a cornercorner with one LiO6 octahedra, corners with six CrO4 tetrahedra, a cornercorner with one LiO5 trigonal bipyramid, and an edgeedge with one LiO6 octahedra. The corner-sharing octahedral tilt angles are 76°. There are a spread of Li–O bond distances ranging from 2.07–2.72 Å. In the third Li1+ site, Li1+ is bonded in a 7-coordinate geometry to seven O2- atoms. There are a spread of Li–O bond distances ranging from 2.08–2.79 Å. In the fourth Li1+ site, Li1+ is bonded to five O2- atoms to form distorted LiO5 trigonal bipyramids that share a cornercorner with one LiO6 octahedra and corners with six CrO4 tetrahedra. The corner-sharing octahedral tilt angles are 56°. There are a spread of Li–O bond distances ranging from 2.09–2.35 Å. There are four inequivalent Cr6+ sites. In the first Cr6+ site, Cr6+ is bonded to four O2- atoms to form CrO4 tetrahedra that share corners with two LiO6 octahedra, a cornercorner with one CrO4 tetrahedra, and corners with two equivalent LiO5 trigonal bipyramids. The corner-sharing octahedra tilt angles range from 40–66°. There are a spread of Cr–O bond distances ranging from 1.63–1.77 Å. In the second Cr6+ site, Cr6+ is bonded to four O2- atoms to form CrO4 tetrahedra that share corners with three LiO6 octahedra, a cornercorner with one CrO4 tetrahedra, and corners with two equivalent LiO5 trigonal bipyramids. The corner-sharing octahedra tilt angles range from 44–57°. There is three shorter (1.63 Å) and one longer (1.82 Å) Cr–O bond length. In the third Cr6+ site, Cr6+ is bonded to four O2- atoms to form CrO4 tetrahedra that share corners with three LiO6 octahedra, a cornercorner with one CrO4 tetrahedra, and a cornercorner with one LiO5 trigonal bipyramid. The corner-sharing octahedra tilt angles range from 50–71°. There are a spread of Cr–O bond distances ranging from 1.63–1.80 Å. In the fourth Cr6+ site, Cr6+ is bonded to four O2- atoms to form CrO4 tetrahedra that share corners with four LiO6 octahedra, a cornercorner with one CrO4 tetrahedra, and a cornercorner with one LiO5 trigonal bipyramid. The corner-sharing octahedra tilt angles range from 44–68°. There are a spread of Cr–O bond distances ranging from 1.63–1.80 Å. There are fourteen inequivalent O2- sites. In the first O2- site, O2- is bonded in a 3-coordinate geometry to two Li1+ and one Cr6+ atom. In the second O2- site, O2- is bonded in a 2-coordinate geometry to two Li1+ and one Cr6+ atom. In the third O2- site, O2- is bonded in a 3-coordinate geometry to two Li1+ and one Cr6+ atom. In the fourth O2- site, O2- is bonded in a 3-coordinate geometry to two Li1+ and one Cr6+ atom. In the fifth O2- site, O2- is bonded in a distorted trigonal planar geometry to two Li1+ and one Cr6+ atom. In the sixth O2- site, O2- is bonded in a distorted bent 150 degrees geometry to two Cr6+ atoms. In the seventh O2- site, O2- is bonded in a 2-coordinate geometry to two Li1+ and one Cr6+ atom. In the eighth O2- site, O2- is bonded in a distorted trigonal planar geometry to two Li1+ and one Cr6+ atom. In the ninth O2- site, O2- is bonded in a distorted bent 150 degrees geometry to one Li1+ and one Cr6+ atom. In the tenth O2- site, O2- is bonded in a 3-coordinate geometry to two Li1+ and one Cr6+ atom. In the eleventh O2- site, O2- is bonded in a distorted trigonal non-coplanar geometry to one Li1+ and two Cr6+ atoms. In the twelfth O2- site, O2- is bonded in a 1-coordinate geometry to two Li1+ and one Cr6+ atom. In the thirteenth O2- site, O2- is bonded in a 3-coordinate geometry to two Li1+ and one Cr6+ atom. In the fourteenth O2- site, O2- is bonded in a distorted bent 120 degrees geometry to two Li1+ and one Cr6+ atom.