Li2Cr2O7 crystallizes in the triclinic P-1 space group. There are four inequivalent Li sites. In the first Li site, Li(1) is bonded to one O(1), one O(2), one O(3), one O(4), one O(8), and one O(9) atom to form distorted LiO6 octahedra that share  a cornercorner with one Li(2)O5 square pyramid,  a cornercorner with one Cr(1)O4 tetrahedra,  a cornercorner with one Cr(3)O4 tetrahedra, corners with two equivalent Cr(2)O4 tetrahedra, corners with two equivalent Cr(4)O4 tetrahedra, and  an edgeedge with one Li(2)O5 square pyramid. In the second Li site, Li(2) is bonded to one O(1), one O(14), one O(3), one O(5), and one O(8) atom to form distorted LiO5 square pyramids that share  a cornercorner with one Li(1)O6 octahedra,  a cornercorner with one Cr(1)O4 tetrahedra,  a cornercorner with one Cr(2)O4 tetrahedra,  a cornercorner with one Cr(3)O4 tetrahedra, corners with two equivalent Cr(4)O4 tetrahedra,  a cornercorner with one Li(4)O5 trigonal bipyramid, and  an edgeedge with one Li(1)O6 octahedra. The corner-sharing octahedral tilt angles are 76°. In the third Li site, Li(3) is bonded in a 6-coordinate geometry to one O(10), one O(12), one O(13), one O(2), one O(4), and one O(7) atom. In the fourth Li site, Li(4) is bonded to one O(10), one O(11), one O(12), one O(13), and one O(5) atom to form LiO5 trigonal bipyramids that share  a cornercorner with one Li(2)O5 square pyramid,  a cornercorner with one Cr(3)O4 tetrahedra,  a cornercorner with one Cr(4)O4 tetrahedra, corners with two equivalent Cr(1)O4 tetrahedra, and corners with two equivalent Cr(2)O4 tetrahedra. There are four inequivalent Cr sites. In the first Cr site, Cr(1) is bonded to one O(13), one O(2), one O(5), and one O(6) atom to form CrO4 tetrahedra that share  a cornercorner with one Li(1)O6 octahedra,  a cornercorner with one Li(2)O5 square pyramid,  a cornercorner with one Cr(3)O4 tetrahedra, and corners with two equivalent Li(4)O5 trigonal bipyramids. The corner-sharing octahedral tilt angles are 40°. In the second Cr site, Cr(2) is bonded to one O(10), one O(11), one O(3), and one O(9) atom to form CrO4 tetrahedra that share corners with two equivalent Li(1)O6 octahedra,  a cornercorner with one Li(2)O5 square pyramid,  a cornercorner with one Cr(4)O4 tetrahedra, and corners with two equivalent Li(4)O5 trigonal bipyramids. The corner-sharing octahedral tilt angles range from 44-57°. In the third Cr site, Cr(3) is bonded to one O(1), one O(12), one O(6), and one O(7) atom to form CrO4 tetrahedra that share  a cornercorner with one Li(1)O6 octahedra,  a cornercorner with one Li(2)O5 square pyramid,  a cornercorner with one Cr(1)O4 tetrahedra, and  a cornercorner with one Li(4)O5 trigonal bipyramid. The corner-sharing octahedral tilt angles are 56°. In the fourth Cr site, Cr(4) is bonded to one O(11), one O(14), one O(4), and one O(8) atom to form CrO4 tetrahedra that share corners with two equivalent Li(1)O6 octahedra, corners with two equivalent Li(2)O5 square pyramids,  a cornercorner with one Cr(2)O4 tetrahedra, and  a cornercorner with one Li(4)O5 trigonal bipyramid. The corner-sharing octahedral tilt angles range from 62-68°. There are fourteen inequivalent O sites. In the first O site, O(1) is bonded in a distorted trigonal planar geometry to one Li(1), one Li(2), and one Cr(3) atom. In the second O site, O(2) is bonded in a 2-coordinate geometry to one Li(1), one Li(3), and one Cr(1) atom. In the third O site, O(3) is bonded in a distorted trigonal planar geometry to one Li(1), one Li(2), and one Cr(2) atom. In the fourth O site, O(4) is bonded in a distorted trigonal planar geometry to one Li(1), one Li(3), and one Cr(4) atom. In the fifth O site, O(5) is bonded in a trigonal planar geometry to one Li(2), one Li(4), and one Cr(1) atom. In the sixth O site, O(6) is bonded in a bent 150 degrees geometry to one Cr(1) and one Cr(3) atom. In the seventh O site, O(7) is bonded in a distorted bent 150 degrees geometry to one Li(3) and one Cr(3) atom. In the eighth O site, O(8) is bonded in a distorted trigonal planar geometry to one Li(1), one Li(2), and one Cr(4) atom. In the ninth O site, O(9) is bonded in a distorted bent 150 degrees geometry to one Li(1) and one Cr(2) atom. In the tenth O site, O(10) is bonded in a 3-coordinate geometry to one Li(3), one Li(4), and one Cr(2) atom. In the eleventh O site, O(11) is bonded in a distorted trigonal non-coplanar geometry to one Li(4), one Cr(2), and one Cr(4) atom. In the twelfth O site, O(12) is bonded in a 3-coordinate geometry to one Li(3), one Li(4), and one Cr(3) atom. In the thirteenth O site, O(13) is bonded in a distorted trigonal planar geometry to one Li(3), one Li(4), and one Cr(1) atom. In the fourteenth O site, O(14) is bonded in a bent 120 degrees geometry to one Li(2) and one Cr(4) atom.
Li2Cr2O7 crystallizes in the triclinic P-1 space group. There are four inequivalent Li sites. In the first Li site, Li(1) is bonded to one O(1), one O(2), one O(3), one O(4), one O(8), and one O(9) atom to form distorted LiO6 octahedra that share  a cornercorner with one Li(2)O5 square pyramid,  a cornercorner with one Cr(1)O4 tetrahedra,  a cornercorner with one Cr(3)O4 tetrahedra, corners with two equivalent Cr(2)O4 tetrahedra, corners with two equivalent Cr(4)O4 tetrahedra, and  an edgeedge with one Li(2)O5 square pyramid. The Li(1)-O(1) bond length is 2.48 Å. The Li(1)-O(2) bond length is 2.12 Å. The Li(1)-O(3) bond length is 2.32 Å. The Li(1)-O(4) bond length is 2.25 Å. The Li(1)-O(8) bond length is 2.28 Å. The Li(1)-O(9) bond length is 2.07 Å. In the second Li site, Li(2) is bonded to one O(1), one O(14), one O(3), one O(5), and one O(8) atom to form distorted LiO5 square pyramids that share  a cornercorner with one Li(1)O6 octahedra,  a cornercorner with one Cr(1)O4 tetrahedra,  a cornercorner with one Cr(2)O4 tetrahedra,  a cornercorner with one Cr(3)O4 tetrahedra, corners with two equivalent Cr(4)O4 tetrahedra,  a cornercorner with one Li(4)O5 trigonal bipyramid, and  an edgeedge with one Li(1)O6 octahedra. The corner-sharing octahedral tilt angles are 76°. The Li(2)-O(1) bond length is 2.07 Å. The Li(2)-O(14) bond length is 2.14 Å. The Li(2)-O(3) bond length is 2.30 Å. The Li(2)-O(5) bond length is 2.34 Å. The Li(2)-O(8) bond length is 2.08 Å. In the third Li site, Li(3) is bonded in a 6-coordinate geometry to one O(10), one O(12), one O(13), one O(2), one O(4), and one O(7) atom. The Li(3)-O(10) bond length is 2.52 Å. The Li(3)-O(12) bond length is 2.60 Å. The Li(3)-O(13) bond length is 2.31 Å. The Li(3)-O(2) bond length is 2.59 Å. The Li(3)-O(4) bond length is 2.08 Å. The Li(3)-O(7) bond length is 2.12 Å. In the fourth Li site, Li(4) is bonded to one O(10), one O(11), one O(12), one O(13), and one O(5) atom to form LiO5 trigonal bipyramids that share  a cornercorner with one Li(2)O5 square pyramid,  a cornercorner with one Cr(3)O4 tetrahedra,  a cornercorner with one Cr(4)O4 tetrahedra, corners with two equivalent Cr(1)O4 tetrahedra, and corners with two equivalent Cr(2)O4 tetrahedra. The Li(4)-O(10) bond length is 2.09 Å. The Li(4)-O(11) bond length is 2.30 Å. The Li(4)-O(12) bond length is 2.35 Å. The Li(4)-O(13) bond length is 2.09 Å. The Li(4)-O(5) bond length is 2.22 Å. There are four inequivalent Cr sites. In the first Cr site, Cr(1) is bonded to one O(13), one O(2), one O(5), and one O(6) atom to form CrO4 tetrahedra that share  a cornercorner with one Li(1)O6 octahedra,  a cornercorner with one Li(2)O5 square pyramid,  a cornercorner with one Cr(3)O4 tetrahedra, and corners with two equivalent Li(4)O5 trigonal bipyramids. The corner-sharing octahedral tilt angles are 40°. The Cr(1)-O(13) bond length is 1.65 Å. The Cr(1)-O(2) bond length is 1.63 Å. The Cr(1)-O(5) bond length is 1.64 Å. The Cr(1)-O(6) bond length is 1.77 Å. In the second Cr site, Cr(2) is bonded to one O(10), one O(11), one O(3), and one O(9) atom to form CrO4 tetrahedra that share corners with two equivalent Li(1)O6 octahedra,  a cornercorner with one Li(2)O5 square pyramid,  a cornercorner with one Cr(4)O4 tetrahedra, and corners with two equivalent Li(4)O5 trigonal bipyramids. The corner-sharing octahedral tilt angles range from 44-57°. The Cr(2)-O(10) bond length is 1.63 Å. The Cr(2)-O(11) bond length is 1.82 Å. The Cr(2)-O(3) bond length is 1.63 Å. The Cr(2)-O(9) bond length is 1.63 Å. In the third Cr site, Cr(3) is bonded to one O(1), one O(12), one O(6), and one O(7) atom to form CrO4 tetrahedra that share  a cornercorner with one Li(1)O6 octahedra,  a cornercorner with one Li(2)O5 square pyramid,  a cornercorner with one Cr(1)O4 tetrahedra, and  a cornercorner with one Li(4)O5 trigonal bipyramid. The corner-sharing octahedral tilt angles are 56°. The Cr(3)-O(1) bond length is 1.64 Å. The Cr(3)-O(12) bond length is 1.63 Å. The Cr(3)-O(6) bond length is 1.80 Å. The Cr(3)-O(7) bond length is 1.64 Å. In the fourth Cr site, Cr(4) is bonded to one O(11), one O(14), one O(4), and one O(8) atom to form CrO4 tetrahedra that share corners with two equivalent Li(1)O6 octahedra, corners with two equivalent Li(2)O5 square pyramids,  a cornercorner with one Cr(2)O4 tetrahedra, and  a cornercorner with one Li(4)O5 trigonal bipyramid. The corner-sharing octahedral tilt angles range from 62-68°. The Cr(4)-O(11) bond length is 1.80 Å. The Cr(4)-O(14) bond length is 1.63 Å. The Cr(4)-O(4) bond length is 1.64 Å. The Cr(4)-O(8) bond length is 1.64 Å. There are fourteen inequivalent O sites. In the first O site, O(1) is bonded in a distorted trigonal planar geometry to one Li(1), one Li(2), and one Cr(3) atom. In the second O site, O(2) is bonded in a 2-coordinate geometry to one Li(1), one Li(3), and one Cr(1) atom. In the third O site, O(3) is bonded in a distorted trigonal planar geometry to one Li(1), one Li(2), and one Cr(2) atom. In the fourth O site, O(4) is bonded in a distorted trigonal planar geometry to one Li(1), one Li(3), and one Cr(4) atom. In the fifth O site, O(5) is bonded in a trigonal planar geometry to one Li(2), one Li(4), and one Cr(1) atom. In the sixth O site, O(6) is bonded in a bent 150 degrees geometry to one Cr(1) and one Cr(3) atom. In the seventh O site, O(7) is bonded in a distorted bent 150 degrees geometry to one Li(3) and one Cr(3) atom. In the eighth O site, O(8) is bonded in a distorted trigonal planar geometry to one Li(1), one Li(2), and one Cr(4) atom. In the ninth O site, O(9) is bonded in a distorted bent 150 degrees geometry to one Li(1) and one Cr(2) atom. In the tenth O site, O(10) is bonded in a 3-coordinate geometry to one Li(3), one Li(4), and one Cr(2) atom. In the eleventh O site, O(11) is bonded in a distorted trigonal non-coplanar geometry to one Li(4), one Cr(2), and one Cr(4) atom. In the twelfth O site, O(12) is bonded in a 3-coordinate geometry to one Li(3), one Li(4), and one Cr(3) atom. In the thirteenth O site, O(13) is bonded in a distorted trigonal planar geometry to one Li(3), one Li(4), and one Cr(1) atom. In the fourteenth O site, O(14) is bonded in a bent 120 degrees geometry to one Li(2) and one Cr(4) atom.