Li2Cr2O7 crystallizes in the orthorhombic Cmce space group. There are two inequivalent Li sites. In the first Li site, Li(1) is bonded to two equivalent O(1), two equivalent O(3), and two equivalent O(5) atoms to form LiO6 octahedra that share corners with four equivalent Cr(2)O4 tetrahedra, edges with two equivalent Li(1)O6 octahedra, and edges with two equivalent Li(2)O6 pentagonal pyramids. In the second Li site, Li(2) is bonded to one O(3), one O(4), two equivalent O(1), and two equivalent O(2) atoms to form distorted LiO6 pentagonal pyramids that share corners with three equivalent Cr(2)O4 tetrahedra and edges with two equivalent Li(1)O6 octahedra. There are two inequivalent Cr sites. In the first Cr site, Cr(1) is bonded in a 6-coordinate geometry to two equivalent O(1), two equivalent O(2), and two equivalent O(4) atoms. In the second Cr site, Cr(2) is bonded to one O(3), one O(5), and two equivalent O(2) atoms to form CrO4 tetrahedra that share corners with four equivalent Li(1)O6 octahedra and corners with three equivalent Li(2)O6 pentagonal pyramids. The corner-sharing octahedral tilt angles range from 53-60°. There are five inequivalent O sites. In the first O site, O(1) is bonded in a 3-coordinate geometry to one Li(1), one Li(2), and one Cr(1) atom. In the second O site, O(2) is bonded in a 3-coordinate geometry to one Li(2), one Cr(1), and one Cr(2) atom. In the third O site, O(3) is bonded to one Li(2), two equivalent Li(1), and one Cr(2) atom to form distorted edge-sharing OLi3Cr tetrahedra. In the fourth O site, O(4) is bonded in a distorted trigonal planar geometry to one Li(2) and two equivalent Cr(1) atoms. In the fifth O site, O(5) is bonded in a trigonal planar geometry to two equivalent Li(1) and one Cr(2) atom.
Li2Cr2O7 crystallizes in the orthorhombic Cmce space group. There are two inequivalent Li sites. In the first Li site, Li(1) is bonded to two equivalent O(1), two equivalent O(3), and two equivalent O(5) atoms to form LiO6 octahedra that share corners with four equivalent Cr(2)O4 tetrahedra, edges with two equivalent Li(1)O6 octahedra, and edges with two equivalent Li(2)O6 pentagonal pyramids. Both Li(1)-O(1) bond lengths are 2.27 Å. Both Li(1)-O(3) bond lengths are 2.24 Å. Both Li(1)-O(5) bond lengths are 2.15 Å. In the second Li site, Li(2) is bonded to one O(3), one O(4), two equivalent O(1), and two equivalent O(2) atoms to form distorted LiO6 pentagonal pyramids that share corners with three equivalent Cr(2)O4 tetrahedra and edges with two equivalent Li(1)O6 octahedra. The Li(2)-O(3) bond length is 2.05 Å. The Li(2)-O(4) bond length is 2.27 Å. Both Li(2)-O(1) bond lengths are 2.37 Å. Both Li(2)-O(2) bond lengths are 2.13 Å. There are two inequivalent Cr sites. In the first Cr site, Cr(1) is bonded in a 6-coordinate geometry to two equivalent O(1), two equivalent O(2), and two equivalent O(4) atoms. Both Cr(1)-O(1) bond lengths are 1.62 Å. Both Cr(1)-O(2) bond lengths are 2.30 Å. Both Cr(1)-O(4) bond lengths are 1.81 Å. In the second Cr site, Cr(2) is bonded to one O(3), one O(5), and two equivalent O(2) atoms to form CrO4 tetrahedra that share corners with four equivalent Li(1)O6 octahedra and corners with three equivalent Li(2)O6 pentagonal pyramids. The corner-sharing octahedral tilt angles range from 53-60°. The Cr(2)-O(3) bond length is 1.68 Å. The Cr(2)-O(5) bond length is 1.65 Å. Both Cr(2)-O(2) bond lengths are 1.67 Å. There are five inequivalent O sites. In the first O site, O(1) is bonded in a 3-coordinate geometry to one Li(1), one Li(2), and one Cr(1) atom. In the second O site, O(2) is bonded in a 3-coordinate geometry to one Li(2), one Cr(1), and one Cr(2) atom. In the third O site, O(3) is bonded to one Li(2), two equivalent Li(1), and one Cr(2) atom to form distorted edge-sharing OLi3Cr tetrahedra. In the fourth O site, O(4) is bonded in a distorted trigonal planar geometry to one Li(2) and two equivalent Cr(1) atoms. In the fifth O site, O(5) is bonded in a trigonal planar geometry to two equivalent Li(1) and one Cr(2) atom.