Li2Cr3(P2O7)2 crystallizes in the triclinic P-1 space group. Li(1) is bonded in a 5-coordinate geometry to one O(1), one O(2), one O(4), one O(5), and one O(6) atom. There are two inequivalent Cr sites. In the first Cr site, Cr(1) is bonded to one O(1), one O(2), one O(6), and two equivalent O(3) atoms to form distorted CrO5 square pyramids that share corners with two equivalent P(2)O4 tetrahedra, corners with three equivalent P(1)O4 tetrahedra, and  an edgeedge with one Cr(1)O5 square pyramid. In the second Cr site, Cr(2) is bonded in a square co-planar geometry to two equivalent O(4) and two equivalent O(5) atoms. There are two inequivalent P sites. In the first P site, P(1) is bonded to one O(2), one O(3), one O(5), and one O(7) atom to form PO4 tetrahedra that share corners with three equivalent Cr(1)O5 square pyramids and  a cornercorner with one P(2)O4 tetrahedra. In the second P site, P(2) is bonded to one O(1), one O(4), one O(6), and one O(7) atom to form PO4 tetrahedra that share corners with two equivalent Cr(1)O5 square pyramids and  a cornercorner with one P(1)O4 tetrahedra. There are seven inequivalent O sites. In the first O site, O(1) is bonded in a distorted trigonal planar geometry to one Li(1), one Cr(1), and one P(2) atom. In the second O site, O(2) is bonded in a 3-coordinate geometry to one Li(1), one Cr(1), and one P(1) atom. In the third O site, O(3) is bonded in a distorted trigonal planar geometry to two equivalent Cr(1) and one P(1) atom. In the fourth O site, O(4) is bonded in a 3-coordinate geometry to one Li(1), one Cr(2), and one P(2) atom. In the fifth O site, O(5) is bonded in a distorted trigonal planar geometry to one Li(1), one Cr(2), and one P(1) atom. In the sixth O site, O(6) is bonded in a distorted trigonal planar geometry to one Li(1), one Cr(1), and one P(2) atom. In the seventh O site, O(7) is bonded in a bent 150 degrees geometry to one P(1) and one P(2) atom.
Li2Cr3(P2O7)2 crystallizes in the triclinic P-1 space group. Li(1) is bonded in a 5-coordinate geometry to one O(1), one O(2), one O(4), one O(5), and one O(6) atom. The Li(1)-O(1) bond length is 2.12 Å. The Li(1)-O(2) bond length is 2.04 Å. The Li(1)-O(4) bond length is 2.40 Å. The Li(1)-O(5) bond length is 2.29 Å. The Li(1)-O(6) bond length is 2.12 Å. There are two inequivalent Cr sites. In the first Cr site, Cr(1) is bonded to one O(1), one O(2), one O(6), and two equivalent O(3) atoms to form distorted CrO5 square pyramids that share corners with two equivalent P(2)O4 tetrahedra, corners with three equivalent P(1)O4 tetrahedra, and  an edgeedge with one Cr(1)O5 square pyramid. The Cr(1)-O(1) bond length is 2.06 Å. The Cr(1)-O(2) bond length is 2.56 Å. The Cr(1)-O(6) bond length is 2.06 Å. There is one shorter (2.09 Å) and one longer (2.10 Å) Cr(1)-O(3) bond length. In the second Cr site, Cr(2) is bonded in a square co-planar geometry to two equivalent O(4) and two equivalent O(5) atoms. Both Cr(2)-O(4) bond lengths are 2.07 Å. Both Cr(2)-O(5) bond lengths are 2.10 Å. There are two inequivalent P sites. In the first P site, P(1) is bonded to one O(2), one O(3), one O(5), and one O(7) atom to form PO4 tetrahedra that share corners with three equivalent Cr(1)O5 square pyramids and  a cornercorner with one P(2)O4 tetrahedra. The P(1)-O(2) bond length is 1.51 Å. The P(1)-O(3) bond length is 1.56 Å. The P(1)-O(5) bond length is 1.53 Å. The P(1)-O(7) bond length is 1.64 Å. In the second P site, P(2) is bonded to one O(1), one O(4), one O(6), and one O(7) atom to form PO4 tetrahedra that share corners with two equivalent Cr(1)O5 square pyramids and  a cornercorner with one P(1)O4 tetrahedra. The P(2)-O(1) bond length is 1.53 Å. The P(2)-O(4) bond length is 1.53 Å. The P(2)-O(6) bond length is 1.54 Å. The P(2)-O(7) bond length is 1.61 Å. There are seven inequivalent O sites. In the first O site, O(1) is bonded in a distorted trigonal planar geometry to one Li(1), one Cr(1), and one P(2) atom. In the second O site, O(2) is bonded in a 3-coordinate geometry to one Li(1), one Cr(1), and one P(1) atom. In the third O site, O(3) is bonded in a distorted trigonal planar geometry to two equivalent Cr(1) and one P(1) atom. In the fourth O site, O(4) is bonded in a 3-coordinate geometry to one Li(1), one Cr(2), and one P(2) atom. In the fifth O site, O(5) is bonded in a distorted trigonal planar geometry to one Li(1), one Cr(2), and one P(1) atom. In the sixth O site, O(6) is bonded in a distorted trigonal planar geometry to one Li(1), one Cr(1), and one P(2) atom. In the seventh O site, O(7) is bonded in a bent 150 degrees geometry to one P(1) and one P(2) atom.