Li2CoP2O7 crystallizes in the triclinic P-1 space group. There are two inequivalent Li sites. In the first Li site, Li(1) is bonded in a see-saw-like geometry to one O(2), one O(4), and two equivalent O(5) atoms. In the second Li site, Li(2) is bonded to one O(1), one O(3), and two equivalent O(7) atoms to form distorted LiO4 tetrahedra that share corners with two equivalent Co(1)O5 square pyramids,  a cornercorner with one P(1)O4 tetrahedra, corners with three equivalent P(2)O4 tetrahedra,  an edgeedge with one Co(1)O5 square pyramid, and  an edgeedge with one Li(2)O4 tetrahedra. Co(1) is bonded to one O(1), one O(2), one O(3), one O(4), and one O(7) atom to form CoO5 square pyramids that share corners with two equivalent Li(2)O4 tetrahedra, corners with two equivalent P(2)O4 tetrahedra, corners with three equivalent P(1)O4 tetrahedra, and  an edgeedge with one Li(2)O4 tetrahedra. 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(6) atom to form PO4 tetrahedra that share corners with three equivalent Co(1)O5 square pyramids,  a cornercorner with one Li(2)O4 tetrahedra, and  a cornercorner with one P(2)O4 tetrahedra. In the second P site, P(2) is bonded to one O(3), one O(5), one O(6), and one O(7) atom to form PO4 tetrahedra that share corners with two equivalent Co(1)O5 square pyramids,  a cornercorner with one P(1)O4 tetrahedra, and corners with three equivalent Li(2)O4 tetrahedra. There are seven inequivalent O sites. In the first O site, O(1) is bonded in a trigonal planar geometry to one Li(2), one Co(1), and one P(1) 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 distorted 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(1), one Co(1), and one P(1) atom. In the fifth O site, O(5) is bonded in a distorted trigonal planar geometry to two equivalent Li(1) and one P(2) atom. In the sixth O site, O(6) is bonded in a bent 120 degrees geometry to one P(1) and one P(2) atom. In the seventh O site, O(7) is bonded to two equivalent Li(2), one Co(1), and one P(2) atom to form distorted edge-sharing OLi2CoP trigonal pyramids.
Li2CoP2O7 crystallizes in the triclinic P-1 space group. There are two inequivalent Li sites. In the first Li site, Li(1) is bonded in a see-saw-like geometry to one O(2), one O(4), and two equivalent O(5) atoms. The Li(1)-O(2) bond length is 2.14 Å. The Li(1)-O(4) bond length is 2.12 Å. There is one shorter (1.99 Å) and one longer (2.05 Å) Li(1)-O(5) bond length. In the second Li site, Li(2) is bonded to one O(1), one O(3), and two equivalent O(7) atoms to form distorted LiO4 tetrahedra that share corners with two equivalent Co(1)O5 square pyramids,  a cornercorner with one P(1)O4 tetrahedra, corners with three equivalent P(2)O4 tetrahedra,  an edgeedge with one Co(1)O5 square pyramid, and  an edgeedge with one Li(2)O4 tetrahedra. The Li(2)-O(1) bond length is 1.92 Å. The Li(2)-O(3) bond length is 1.92 Å. There is one shorter (1.95 Å) and one longer (2.10 Å) Li(2)-O(7) bond length. Co(1) is bonded to one O(1), one O(2), one O(3), one O(4), and one O(7) atom to form CoO5 square pyramids that share corners with two equivalent Li(2)O4 tetrahedra, corners with two equivalent P(2)O4 tetrahedra, corners with three equivalent P(1)O4 tetrahedra, and  an edgeedge with one Li(2)O4 tetrahedra. The Co(1)-O(1) bond length is 2.08 Å. The Co(1)-O(2) bond length is 2.09 Å. The Co(1)-O(3) bond length is 2.08 Å. The Co(1)-O(4) bond length is 2.04 Å. The Co(1)-O(7) bond length is 2.15 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(6) atom to form PO4 tetrahedra that share corners with three equivalent Co(1)O5 square pyramids,  a cornercorner with one Li(2)O4 tetrahedra, and  a cornercorner with one P(2)O4 tetrahedra. The P(1)-O(1) bond length is 1.54 Å. The P(1)-O(2) bond length is 1.54 Å. The P(1)-O(4) bond length is 1.54 Å. The P(1)-O(6) bond length is 1.63 Å. In the second P site, P(2) is bonded to one O(3), one O(5), one O(6), and one O(7) atom to form PO4 tetrahedra that share corners with two equivalent Co(1)O5 square pyramids,  a cornercorner with one P(1)O4 tetrahedra, and corners with three equivalent Li(2)O4 tetrahedra. The P(2)-O(3) bond length is 1.54 Å. The P(2)-O(5) bond length is 1.51 Å. The P(2)-O(6) bond length is 1.63 Å. The P(2)-O(7) bond length is 1.55 Å. There are seven inequivalent O sites. In the first O site, O(1) is bonded in a trigonal planar geometry to one Li(2), one Co(1), and one P(1) 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 distorted 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(1), one Co(1), and one P(1) atom. In the fifth O site, O(5) is bonded in a distorted trigonal planar geometry to two equivalent Li(1) and one P(2) atom. In the sixth O site, O(6) is bonded in a bent 120 degrees geometry to one P(1) and one P(2) atom. In the seventh O site, O(7) is bonded to two equivalent Li(2), one Co(1), and one P(2) atom to form distorted edge-sharing OLi2CoP trigonal pyramids.