Li2CoP2O7 crystallizes in the triclinic P-1 space group. There are two inequivalent Li sites. In the first Li site, Li(1) is bonded to one O(2), one O(6), one O(7), and two equivalent O(4) atoms to form distorted LiO5 trigonal bipyramids that share corners with three equivalent Co(1)O6 octahedra,  a cornercorner with one P(1)O4 tetrahedra, corners with four equivalent P(2)O4 tetrahedra,  an edgeedge with one Co(1)O6 octahedra, and  an edgeedge with one Li(1)O5 trigonal bipyramid. The corner-sharing octahedral tilt angles range from 59-67°. In the second Li site, Li(2) is bonded in a 4-coordinate geometry to one O(1), one O(3), one O(5), and one O(6) atom. Co(1) is bonded to one O(1), one O(2), one O(3), one O(4), one O(6), and one O(7) atom to form distorted CoO6 octahedra that share corners with three equivalent P(1)O4 tetrahedra, corners with three equivalent P(2)O4 tetrahedra, corners with three equivalent Li(1)O5 trigonal bipyramids, and  an edgeedge with one Li(1)O5 trigonal bipyramid. There are two inequivalent P sites. In the first P site, P(1) is bonded to one O(1), one O(3), one O(5), and one O(7) atom to form PO4 tetrahedra that share corners with three equivalent Co(1)O6 octahedra,  a cornercorner with one P(2)O4 tetrahedra, and  a cornercorner with one Li(1)O5 trigonal bipyramid. The corner-sharing octahedral tilt angles range from 36-51°. In the second P site, P(2) is bonded to one O(2), one O(4), one O(5), and one O(6) atom to form PO4 tetrahedra that share corners with three equivalent Co(1)O6 octahedra,  a cornercorner with one P(1)O4 tetrahedra, and corners with four equivalent Li(1)O5 trigonal bipyramids. The corner-sharing octahedral tilt angles range from 34-72°. 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 distorted trigonal planar geometry to one Li(1), one Co(1), and one P(2) 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(1) atom. In the fourth O site, O(4) is bonded in a 4-coordinate geometry to two equivalent Li(1), one Co(1), and one P(2) atom. In the fifth O site, O(5) is bonded in a 3-coordinate geometry to one Li(2), one P(1), and one P(2) atom. In the sixth O site, O(6) is bonded in a 4-coordinate geometry to one Li(1), one Li(2), one Co(1), 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 Co(1), and one P(1) atom.
Li2CoP2O7 crystallizes in the triclinic P-1 space group. There are two inequivalent Li sites. In the first Li site, Li(1) is bonded to one O(2), one O(6), one O(7), and two equivalent O(4) atoms to form distorted LiO5 trigonal bipyramids that share corners with three equivalent Co(1)O6 octahedra,  a cornercorner with one P(1)O4 tetrahedra, corners with four equivalent P(2)O4 tetrahedra,  an edgeedge with one Co(1)O6 octahedra, and  an edgeedge with one Li(1)O5 trigonal bipyramid. The corner-sharing octahedral tilt angles range from 59-67°. The Li(1)-O(2) bond length is 2.12 Å. The Li(1)-O(6) bond length is 2.02 Å. The Li(1)-O(7) bond length is 2.14 Å. There is one shorter (2.14 Å) and one longer (2.25 Å) Li(1)-O(4) bond length. In the second Li site, Li(2) is bonded in a 4-coordinate geometry to one O(1), one O(3), one O(5), and one O(6) atom. The Li(2)-O(1) bond length is 1.97 Å. The Li(2)-O(3) bond length is 1.96 Å. The Li(2)-O(5) bond length is 2.26 Å. The Li(2)-O(6) bond length is 1.98 Å. Co(1) is bonded to one O(1), one O(2), one O(3), one O(4), one O(6), and one O(7) atom to form distorted CoO6 octahedra that share corners with three equivalent P(1)O4 tetrahedra, corners with three equivalent P(2)O4 tetrahedra, corners with three equivalent Li(1)O5 trigonal bipyramids, and  an edgeedge with one Li(1)O5 trigonal bipyramid. The Co(1)-O(1) bond length is 2.10 Å. The Co(1)-O(2) bond length is 1.99 Å. The Co(1)-O(3) bond length is 2.07 Å. The Co(1)-O(4) bond length is 2.47 Å. The Co(1)-O(6) bond length is 2.51 Å. The Co(1)-O(7) bond length is 1.99 Å. There are two inequivalent P sites. In the first P site, P(1) is bonded to one O(1), one O(3), one O(5), and one O(7) atom to form PO4 tetrahedra that share corners with three equivalent Co(1)O6 octahedra,  a cornercorner with one P(2)O4 tetrahedra, and  a cornercorner with one Li(1)O5 trigonal bipyramid. The corner-sharing octahedral tilt angles range from 36-51°. The P(1)-O(1) bond length is 1.54 Å. The P(1)-O(3) bond length is 1.53 Å. The P(1)-O(5) bond length is 1.64 Å. The P(1)-O(7) bond length is 1.52 Å. In the second P site, P(2) is bonded to one O(2), one O(4), one O(5), and one O(6) atom to form PO4 tetrahedra that share corners with three equivalent Co(1)O6 octahedra,  a cornercorner with one P(1)O4 tetrahedra, and corners with four equivalent Li(1)O5 trigonal bipyramids. The corner-sharing octahedral tilt angles range from 34-72°. The P(2)-O(2) bond length is 1.52 Å. The P(2)-O(4) bond length is 1.53 Å. The P(2)-O(5) bond length is 1.67 Å. The P(2)-O(6) bond length is 1.54 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 distorted trigonal planar geometry to one Li(1), one Co(1), and one P(2) 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(1) atom. In the fourth O site, O(4) is bonded in a 4-coordinate geometry to two equivalent Li(1), one Co(1), and one P(2) atom. In the fifth O site, O(5) is bonded in a 3-coordinate geometry to one Li(2), one P(1), and one P(2) atom. In the sixth O site, O(6) is bonded in a 4-coordinate geometry to one Li(1), one Li(2), one Co(1), 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 Co(1), and one P(1) atom.