Li6Cr2O7 crystallizes in the monoclinic P2_1/c space group. There are three inequivalent Li sites. In the first Li site, Li(1) is bonded to one O(1), one O(2), one O(4), and two equivalent O(3) atoms to form LiO5 trigonal bipyramids that share corners with two equivalent Li(3)O5 square pyramids, corners with four equivalent Li(2)O5 square pyramids, corners with three equivalent Li(1)O5 trigonal bipyramids, edges with four equivalent Cr(1)O6 octahedra, edges with two equivalent Li(2)O5 square pyramids, and edges with two equivalent Li(3)O5 square pyramids. In the second Li site, Li(2) is bonded to one O(1), one O(2), one O(4), and two equivalent O(3) atoms to form LiO5 square pyramids that share corners with two equivalent Li(3)O5 square pyramids, corners with three equivalent Li(2)O5 square pyramids, corners with four equivalent Li(1)O5 trigonal bipyramids, edges with four equivalent Cr(1)O6 octahedra, edges with two equivalent Li(3)O5 square pyramids, and edges with two equivalent Li(1)O5 trigonal bipyramids. In the third Li site, Li(3) is bonded to one O(3), two equivalent O(2), and two equivalent O(4) atoms to form distorted LiO5 square pyramids that share corners with three equivalent Cr(1)O6 octahedra, corners with two equivalent Li(2)O5 square pyramids, corners with two equivalent Li(3)O5 square pyramids, corners with two equivalent Li(1)O5 trigonal bipyramids, edges with three equivalent Cr(1)O6 octahedra,  an edgeedge with one Li(3)O5 square pyramid, edges with two equivalent Li(2)O5 square pyramids, and edges with two equivalent Li(1)O5 trigonal bipyramids. The corner-sharing octahedral tilt angles range from 5-16°. Cr(1) is bonded to one O(1), one O(3), two equivalent O(2), and two equivalent O(4) atoms to form CrO6 octahedra that share corners with three equivalent Cr(1)O6 octahedra, corners with three equivalent Li(3)O5 square pyramids,  an edgeedge with one Cr(1)O6 octahedra, edges with three equivalent Li(3)O5 square pyramids, edges with four equivalent Li(2)O5 square pyramids, and edges with four equivalent Li(1)O5 trigonal bipyramids. The corner-sharing octahedral tilt angles range from 0-7°. There are four inequivalent O sites. In the first O site, O(1) is bonded to two equivalent Li(1), two equivalent Li(2), and two equivalent Cr(1) atoms to form OLi4Cr2 octahedra that share corners with six equivalent O(3)Li5Cr octahedra, edges with two equivalent O(3)Li5Cr octahedra, edges with four equivalent O(2)Li4Cr2 octahedra, and edges with four equivalent O(4)Li4Cr2 octahedra. The corner-sharing octahedral tilt angles range from 2-17°. In the second O site, O(2) is bonded to one Li(1), one Li(2), two equivalent Li(3), and two equivalent Cr(1) atoms to form OLi4Cr2 octahedra that share corners with six equivalent O(4)Li4Cr2 octahedra, edges with two equivalent O(1)Li4Cr2 octahedra, edges with two equivalent O(2)Li4Cr2 octahedra, edges with two equivalent O(4)Li4Cr2 octahedra, and edges with four equivalent O(3)Li5Cr octahedra. The corner-sharing octahedral tilt angles range from 4-20°. In the third O site, O(3) is bonded to one Li(3), two equivalent Li(1), two equivalent Li(2), and one Cr(1) atom to form OLi5Cr octahedra that share corners with three equivalent O(1)Li4Cr2 octahedra,  an edgeedge with one O(1)Li4Cr2 octahedra, edges with two equivalent O(3)Li5Cr octahedra, edges with four equivalent O(2)Li4Cr2 octahedra, and edges with four equivalent O(4)Li4Cr2 octahedra. The corner-sharing octahedral tilt angles range from 2-17°. In the fourth O site, O(4) is bonded to one Li(1), one Li(2), two equivalent Li(3), and two equivalent Cr(1) atoms to form OLi4Cr2 octahedra that share corners with six equivalent O(2)Li4Cr2 octahedra, edges with two equivalent O(1)Li4Cr2 octahedra, edges with two equivalent O(2)Li4Cr2 octahedra, edges with two equivalent O(4)Li4Cr2 octahedra, and edges with four equivalent O(3)Li5Cr octahedra. The corner-sharing octahedral tilt angles range from 4-20°.
Li6Cr2O7 crystallizes in the monoclinic P2_1/c space group. There are three inequivalent Li sites. In the first Li site, Li(1) is bonded to one O(1), one O(2), one O(4), and two equivalent O(3) atoms to form LiO5 trigonal bipyramids that share corners with two equivalent Li(3)O5 square pyramids, corners with four equivalent Li(2)O5 square pyramids, corners with three equivalent Li(1)O5 trigonal bipyramids, edges with four equivalent Cr(1)O6 octahedra, edges with two equivalent Li(2)O5 square pyramids, and edges with two equivalent Li(3)O5 square pyramids. The Li(1)-O(1) bond length is 1.99 Å. The Li(1)-O(2) bond length is 2.08 Å. The Li(1)-O(4) bond length is 2.08 Å. There is one shorter (1.95 Å) and one longer (1.98 Å) Li(1)-O(3) bond length. In the second Li site, Li(2) is bonded to one O(1), one O(2), one O(4), and two equivalent O(3) atoms to form LiO5 square pyramids that share corners with two equivalent Li(3)O5 square pyramids, corners with three equivalent Li(2)O5 square pyramids, corners with four equivalent Li(1)O5 trigonal bipyramids, edges with four equivalent Cr(1)O6 octahedra, edges with two equivalent Li(3)O5 square pyramids, and edges with two equivalent Li(1)O5 trigonal bipyramids. The Li(2)-O(1) bond length is 2.01 Å. The Li(2)-O(2) bond length is 2.04 Å. The Li(2)-O(4) bond length is 2.03 Å. There is one shorter (1.99 Å) and one longer (2.01 Å) Li(2)-O(3) bond length. In the third Li site, Li(3) is bonded to one O(3), two equivalent O(2), and two equivalent O(4) atoms to form distorted LiO5 square pyramids that share corners with three equivalent Cr(1)O6 octahedra, corners with two equivalent Li(2)O5 square pyramids, corners with two equivalent Li(3)O5 square pyramids, corners with two equivalent Li(1)O5 trigonal bipyramids, edges with three equivalent Cr(1)O6 octahedra,  an edgeedge with one Li(3)O5 square pyramid, edges with two equivalent Li(2)O5 square pyramids, and edges with two equivalent Li(1)O5 trigonal bipyramids. The corner-sharing octahedral tilt angles range from 5-16°. The Li(3)-O(3) bond length is 1.96 Å. There is one shorter (2.00 Å) and one longer (2.13 Å) Li(3)-O(2) bond length. There is one shorter (2.03 Å) and one longer (2.27 Å) Li(3)-O(4) bond length. Cr(1) is bonded to one O(1), one O(3), two equivalent O(2), and two equivalent O(4) atoms to form CrO6 octahedra that share corners with three equivalent Cr(1)O6 octahedra, corners with three equivalent Li(3)O5 square pyramids,  an edgeedge with one Cr(1)O6 octahedra, edges with three equivalent Li(3)O5 square pyramids, edges with four equivalent Li(2)O5 square pyramids, and edges with four equivalent Li(1)O5 trigonal bipyramids. The corner-sharing octahedral tilt angles range from 0-7°. The Cr(1)-O(1) bond length is 2.07 Å. The Cr(1)-O(3) bond length is 1.83 Å. There is one shorter (1.95 Å) and one longer (2.01 Å) Cr(1)-O(2) bond length. There is one shorter (1.94 Å) and one longer (2.03 Å) Cr(1)-O(4) bond length. There are four inequivalent O sites. In the first O site, O(1) is bonded to two equivalent Li(1), two equivalent Li(2), and two equivalent Cr(1) atoms to form OLi4Cr2 octahedra that share corners with six equivalent O(3)Li5Cr octahedra, edges with two equivalent O(3)Li5Cr octahedra, edges with four equivalent O(2)Li4Cr2 octahedra, and edges with four equivalent O(4)Li4Cr2 octahedra. The corner-sharing octahedral tilt angles range from 2-17°. In the second O site, O(2) is bonded to one Li(1), one Li(2), two equivalent Li(3), and two equivalent Cr(1) atoms to form OLi4Cr2 octahedra that share corners with six equivalent O(4)Li4Cr2 octahedra, edges with two equivalent O(1)Li4Cr2 octahedra, edges with two equivalent O(2)Li4Cr2 octahedra, edges with two equivalent O(4)Li4Cr2 octahedra, and edges with four equivalent O(3)Li5Cr octahedra. The corner-sharing octahedral tilt angles range from 4-20°. In the third O site, O(3) is bonded to one Li(3), two equivalent Li(1), two equivalent Li(2), and one Cr(1) atom to form OLi5Cr octahedra that share corners with three equivalent O(1)Li4Cr2 octahedra,  an edgeedge with one O(1)Li4Cr2 octahedra, edges with two equivalent O(3)Li5Cr octahedra, edges with four equivalent O(2)Li4Cr2 octahedra, and edges with four equivalent O(4)Li4Cr2 octahedra. The corner-sharing octahedral tilt angles range from 2-17°. In the fourth O site, O(4) is bonded to one Li(1), one Li(2), two equivalent Li(3), and two equivalent Cr(1) atoms to form OLi4Cr2 octahedra that share corners with six equivalent O(2)Li4Cr2 octahedra, edges with two equivalent O(1)Li4Cr2 octahedra, edges with two equivalent O(2)Li4Cr2 octahedra, edges with two equivalent O(4)Li4Cr2 octahedra, and edges with four equivalent O(3)Li5Cr octahedra. The corner-sharing octahedral tilt angles range from 4-20°.