Li2Cr2O7 crystallizes in the triclinic P1 space group. There are four inequivalent Li sites. In the first Li site, Li(1) is bonded to one O(2), one O(3), one O(6), one O(8), and one O(9) atom to form LiO5 trigonal bipyramids that share  a cornercorner with one Cr(3)O4 tetrahedra, corners with two equivalent Cr(1)O4 tetrahedra, corners with two equivalent Cr(2)O4 tetrahedra, and  an edgeedge with one Li(2)O4 trigonal pyramid. In the second Li site, Li(2) is bonded to one O(1), one O(14), one O(8), and one O(9) atom to form distorted LiO4 trigonal pyramids that share  a cornercorner with one Cr(2)O4 tetrahedra,  a cornercorner with one Cr(3)O4 tetrahedra, corners with two equivalent Cr(1)O4 tetrahedra, and  an edgeedge with one Li(1)O5 trigonal bipyramid. In the third Li site, Li(3) is bonded in a 4-coordinate geometry to one O(10), one O(12), one O(14), and one O(3) atom. In the fourth Li site, Li(4) is bonded in a see-saw-like geometry to one O(11), one O(13), one O(4), and one O(6) atom. There are four inequivalent Cr sites. In the first Cr site, Cr(1) is bonded to one O(1), one O(11), one O(2), and one O(8) atom to form CrO4 tetrahedra that share  a cornercorner with one Cr(4)O4 tetrahedra, corners with two equivalent Li(1)O5 trigonal bipyramids, and corners with two equivalent Li(2)O4 trigonal pyramids. In the second Cr site, Cr(2) is bonded to one O(3), one O(4), one O(7), and one O(9) atom to form CrO4 tetrahedra that share  a cornercorner with one Cr(4)O4 tetrahedra, corners with two equivalent Li(1)O5 trigonal bipyramids, and  a cornercorner with one Li(2)O4 trigonal pyramid. In the third Cr site, Cr(3) is bonded to one O(12), one O(14), one O(5), and one O(6) atom to form CrO4 tetrahedra that share  a cornercorner with one Li(1)O5 trigonal bipyramid and  a cornercorner with one Li(2)O4 trigonal pyramid. In the fourth Cr site, Cr(4) is bonded to one O(10), one O(11), one O(13), and one O(7) atom to form corner-sharing CrO4 tetrahedra. There are fourteen inequivalent O sites. In the first O site, O(1) is bonded in a linear geometry to one Li(2) and one Cr(1) atom. In the second O site, O(2) is bonded in a bent 150 degrees geometry to one Li(1) and one Cr(1) atom. In the third O site, O(3) is bonded in a trigonal planar geometry to one Li(1), one Li(3), and one Cr(2) atom. In the fourth O site, O(4) is bonded in a distorted bent 150 degrees geometry to one Li(4) and one Cr(2) atom. In the fifth O site, O(5) is bonded in a single-bond geometry to one Cr(3) atom. In the sixth O site, O(6) is bonded in a distorted trigonal planar geometry to one Li(1), one Li(4), and one Cr(3) atom. In the seventh O site, O(7) is bonded in a bent 150 degrees geometry to one Cr(2) and one Cr(4) 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(1) atom. In the ninth O site, O(9) is bonded in a distorted trigonal non-coplanar geometry to one Li(1), one Li(2), and one Cr(2) atom. In the tenth O site, O(10) is bonded in a distorted bent 120 degrees geometry to one Li(3) and one Cr(4) atom. In the eleventh O site, O(11) is bonded in a trigonal planar geometry to one Li(4), one Cr(1), and one Cr(4) atom. In the twelfth O site, O(12) is bonded in a bent 150 degrees geometry to one Li(3) and one Cr(3) atom. In the thirteenth O site, O(13) is bonded in a distorted bent 150 degrees geometry to one Li(4) and one Cr(4) atom. In the fourteenth O site, O(14) is bonded in a 3-coordinate geometry to one Li(2), one Li(3), and one Cr(3) atom.
Li2Cr2O7 crystallizes in the triclinic P1 space group. There are four inequivalent Li sites. In the first Li site, Li(1) is bonded to one O(2), one O(3), one O(6), one O(8), and one O(9) atom to form LiO5 trigonal bipyramids that share  a cornercorner with one Cr(3)O4 tetrahedra, corners with two equivalent Cr(1)O4 tetrahedra, corners with two equivalent Cr(2)O4 tetrahedra, and  an edgeedge with one Li(2)O4 trigonal pyramid. The Li(1)-O(2) bond length is 2.10 Å. The Li(1)-O(3) bond length is 2.33 Å. The Li(1)-O(6) bond length is 2.16 Å. The Li(1)-O(8) bond length is 2.19 Å. The Li(1)-O(9) bond length is 2.12 Å. In the second Li site, Li(2) is bonded to one O(1), one O(14), one O(8), and one O(9) atom to form distorted LiO4 trigonal pyramids that share  a cornercorner with one Cr(2)O4 tetrahedra,  a cornercorner with one Cr(3)O4 tetrahedra, corners with two equivalent Cr(1)O4 tetrahedra, and  an edgeedge with one Li(1)O5 trigonal bipyramid. The Li(2)-O(1) bond length is 2.07 Å. The Li(2)-O(14) bond length is 1.90 Å. The Li(2)-O(8) bond length is 2.15 Å. The Li(2)-O(9) bond length is 2.05 Å. In the third Li site, Li(3) is bonded in a 4-coordinate geometry to one O(10), one O(12), one O(14), and one O(3) atom. The Li(3)-O(10) bond length is 2.11 Å. The Li(3)-O(12) bond length is 2.07 Å. The Li(3)-O(14) bond length is 2.42 Å. The Li(3)-O(3) bond length is 2.12 Å. In the fourth Li site, Li(4) is bonded in a see-saw-like geometry to one O(11), one O(13), one O(4), and one O(6) atom. The Li(4)-O(11) bond length is 2.27 Å. The Li(4)-O(13) bond length is 2.02 Å. The Li(4)-O(4) bond length is 2.12 Å. The Li(4)-O(6) bond length is 1.98 Å. There are four inequivalent Cr sites. In the first Cr site, Cr(1) is bonded to one O(1), one O(11), one O(2), and one O(8) atom to form CrO4 tetrahedra that share  a cornercorner with one Cr(4)O4 tetrahedra, corners with two equivalent Li(1)O5 trigonal bipyramids, and corners with two equivalent Li(2)O4 trigonal pyramids. The Cr(1)-O(1) bond length is 1.61 Å. The Cr(1)-O(11) bond length is 1.87 Å. The Cr(1)-O(2) bond length is 1.63 Å. The Cr(1)-O(8) bond length is 1.64 Å. In the second Cr site, Cr(2) is bonded to one O(3), one O(4), one O(7), and one O(9) atom to form CrO4 tetrahedra that share  a cornercorner with one Cr(4)O4 tetrahedra, corners with two equivalent Li(1)O5 trigonal bipyramids, and  a cornercorner with one Li(2)O4 trigonal pyramid. The Cr(2)-O(3) bond length is 1.63 Å. The Cr(2)-O(4) bond length is 1.63 Å. The Cr(2)-O(7) bond length is 1.80 Å. The Cr(2)-O(9) bond length is 1.64 Å. In the third Cr site, Cr(3) is bonded to one O(12), one O(14), one O(5), and one O(6) atom to form CrO4 tetrahedra that share  a cornercorner with one Li(1)O5 trigonal bipyramid and  a cornercorner with one Li(2)O4 trigonal pyramid. The Cr(3)-O(12) bond length is 1.66 Å. The Cr(3)-O(14) bond length is 1.68 Å. The Cr(3)-O(5) bond length is 1.63 Å. The Cr(3)-O(6) bond length is 1.71 Å. In the fourth Cr site, Cr(4) is bonded to one O(10), one O(11), one O(13), and one O(7) atom to form corner-sharing CrO4 tetrahedra. The Cr(4)-O(10) bond length is 1.61 Å. The Cr(4)-O(11) bond length is 1.74 Å. The Cr(4)-O(13) bond length is 1.62 Å. The Cr(4)-O(7) bond length is 1.74 Å. There are fourteen inequivalent O sites. In the first O site, O(1) is bonded in a linear geometry to one Li(2) and one Cr(1) atom. In the second O site, O(2) is bonded in a bent 150 degrees geometry to one Li(1) and one Cr(1) atom. In the third O site, O(3) is bonded in a trigonal planar geometry to one Li(1), one Li(3), and one Cr(2) atom. In the fourth O site, O(4) is bonded in a distorted bent 150 degrees geometry to one Li(4) and one Cr(2) atom. In the fifth O site, O(5) is bonded in a single-bond geometry to one Cr(3) atom. In the sixth O site, O(6) is bonded in a distorted trigonal planar geometry to one Li(1), one Li(4), and one Cr(3) atom. In the seventh O site, O(7) is bonded in a bent 150 degrees geometry to one Cr(2) and one Cr(4) 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(1) atom. In the ninth O site, O(9) is bonded in a distorted trigonal non-coplanar geometry to one Li(1), one Li(2), and one Cr(2) atom. In the tenth O site, O(10) is bonded in a distorted bent 120 degrees geometry to one Li(3) and one Cr(4) atom. In the eleventh O site, O(11) is bonded in a trigonal planar geometry to one Li(4), one Cr(1), and one Cr(4) atom. In the twelfth O site, O(12) is bonded in a bent 150 degrees geometry to one Li(3) and one Cr(3) atom. In the thirteenth O site, O(13) is bonded in a distorted bent 150 degrees geometry to one Li(4) and one Cr(4) atom. In the fourteenth O site, O(14) is bonded in a 3-coordinate geometry to one Li(2), one Li(3), and one Cr(3) atom.