Li2CoP2O7 crystallizes in the monoclinic C2/c space group. There are three inequivalent Li sites. In the first Li site, Li(1) is bonded to one O(2), one O(5), one O(6), and one O(7) atom to form LiO4 tetrahedra that share corners with two equivalent P(1)O4 tetrahedra, corners with two equivalent P(2)O4 tetrahedra,  a cornercorner with one Li(2)O4 trigonal pyramid, and  a cornercorner with one Li(3)O4 trigonal pyramid. In the second Li site, Li(2) is bonded to two equivalent O(3) and two equivalent O(7) atoms to form distorted LiO4 trigonal pyramids that share corners with two equivalent Li(1)O4 tetrahedra, corners with two equivalent P(1)O4 tetrahedra, and corners with two equivalent P(2)O4 tetrahedra. In the third Li site, Li(3) is bonded to two equivalent O(4) and two equivalent O(6) atoms to form distorted LiO4 trigonal pyramids that share corners with two equivalent Li(1)O4 tetrahedra, corners with two equivalent P(1)O4 tetrahedra, and corners with two equivalent P(2)O4 tetrahedra. Co(1) is bonded in a rectangular see-saw-like geometry to one O(2), one O(3), one O(4), and one O(5) atom. There are two inequivalent P sites. In the first P site, P(1) is bonded to one O(1), one O(2), one O(4), and one O(7) atom to form PO4 tetrahedra that share  a cornercorner with one P(2)O4 tetrahedra, corners with two equivalent Li(1)O4 tetrahedra,  a cornercorner with one Li(2)O4 trigonal pyramid, and  a cornercorner with one Li(3)O4 trigonal pyramid. In the second P site, P(2) is bonded to one O(1), one O(3), one O(5), and one O(6) atom to form PO4 tetrahedra that share  a cornercorner with one P(1)O4 tetrahedra, corners with two equivalent Li(1)O4 tetrahedra,  a cornercorner with one Li(2)O4 trigonal pyramid, and  a cornercorner with one Li(3)O4 trigonal pyramid. There are seven inequivalent O sites. In the first O site, O(1) is bonded in a bent 120 degrees geometry to one P(1) and one P(2) atom. In the second O site, O(2) is bonded in a trigonal planar geometry to one Li(1), one Co(1), and one P(1) atom. In the third O site, O(3) is bonded in a trigonal planar geometry to one Li(2), one Co(1), and one P(2) atom. In the fourth O site, O(4) is bonded in a trigonal planar geometry to one Li(3), one Co(1), and one P(1) atom. In the fifth O site, O(5) is bonded in a trigonal planar geometry to one Li(1), one Co(1), and one P(2) atom. In the sixth O site, O(6) is bonded in a distorted T-shaped geometry to one Li(1), one Li(3), and one P(2) atom. In the seventh O site, O(7) is bonded in a distorted trigonal planar geometry to one Li(1), one Li(2), and one P(1) atom.
Li2CoP2O7 crystallizes in the monoclinic C2/c space group. There are three inequivalent Li sites. In the first Li site, Li(1) is bonded to one O(2), one O(5), one O(6), and one O(7) atom to form LiO4 tetrahedra that share corners with two equivalent P(1)O4 tetrahedra, corners with two equivalent P(2)O4 tetrahedra,  a cornercorner with one Li(2)O4 trigonal pyramid, and  a cornercorner with one Li(3)O4 trigonal pyramid. The Li(1)-O(2) bond length is 2.03 Å. The Li(1)-O(5) bond length is 2.01 Å. The Li(1)-O(6) bond length is 1.90 Å. The Li(1)-O(7) bond length is 1.91 Å. In the second Li site, Li(2) is bonded to two equivalent O(3) and two equivalent O(7) atoms to form distorted LiO4 trigonal pyramids that share corners with two equivalent Li(1)O4 tetrahedra, corners with two equivalent P(1)O4 tetrahedra, and corners with two equivalent P(2)O4 tetrahedra. Both Li(2)-O(3) bond lengths are 2.04 Å. Both Li(2)-O(7) bond lengths are 1.90 Å. In the third Li site, Li(3) is bonded to two equivalent O(4) and two equivalent O(6) atoms to form distorted LiO4 trigonal pyramids that share corners with two equivalent Li(1)O4 tetrahedra, corners with two equivalent P(1)O4 tetrahedra, and corners with two equivalent P(2)O4 tetrahedra. Both Li(3)-O(4) bond lengths are 2.05 Å. Both Li(3)-O(6) bond lengths are 1.92 Å. Co(1) is bonded in a rectangular see-saw-like geometry to one O(2), one O(3), one O(4), and one O(5) atom. The Co(1)-O(2) bond length is 2.03 Å. The Co(1)-O(3) bond length is 2.05 Å. The Co(1)-O(4) bond length is 2.02 Å. The Co(1)-O(5) bond length is 2.07 Å. There are two inequivalent P sites. In the first P site, P(1) is bonded to one O(1), one O(2), one O(4), and one O(7) atom to form PO4 tetrahedra that share  a cornercorner with one P(2)O4 tetrahedra, corners with two equivalent Li(1)O4 tetrahedra,  a cornercorner with one Li(2)O4 trigonal pyramid, and  a cornercorner with one Li(3)O4 trigonal pyramid. The P(1)-O(1) bond length is 1.63 Å. The P(1)-O(2) bond length is 1.55 Å. The P(1)-O(4) bond length is 1.55 Å. The P(1)-O(7) bond length is 1.50 Å. In the second P site, P(2) is bonded to one O(1), one O(3), one O(5), and one O(6) atom to form PO4 tetrahedra that share  a cornercorner with one P(1)O4 tetrahedra, corners with two equivalent Li(1)O4 tetrahedra,  a cornercorner with one Li(2)O4 trigonal pyramid, and  a cornercorner with one Li(3)O4 trigonal pyramid. The P(2)-O(1) bond length is 1.64 Å. The P(2)-O(3) bond length is 1.55 Å. The P(2)-O(5) bond length is 1.55 Å. The P(2)-O(6) bond length is 1.51 Å. There are seven inequivalent O sites. In the first O site, O(1) is bonded in a bent 120 degrees geometry to one P(1) and one P(2) atom. In the second O site, O(2) is bonded in a trigonal planar geometry to one Li(1), one Co(1), and one P(1) atom. In the third O site, O(3) is bonded in a trigonal planar geometry to one Li(2), one Co(1), and one P(2) atom. In the fourth O site, O(4) is bonded in a trigonal planar geometry to one Li(3), one Co(1), and one P(1) atom. In the fifth O site, O(5) is bonded in a trigonal planar geometry to one Li(1), one Co(1), and one P(2) atom. In the sixth O site, O(6) is bonded in a distorted T-shaped geometry to one Li(1), one Li(3), and one P(2) atom. In the seventh O site, O(7) is bonded in a distorted trigonal planar geometry to one Li(1), one Li(2), and one P(1) atom.