Li2CoP2O7 crystallizes in the monoclinic C2/c space group. Li(1) is bonded in a 5-coordinate geometry to one O(1), one O(3), one O(4), and two equivalent O(2) atoms. Co(1) is bonded to two equivalent O(1), two equivalent O(2), and two equivalent O(3) atoms to form CoO6 octahedra that share corners with six equivalent P(1)O4 tetrahedra. P(1) is bonded to one O(1), one O(2), one O(3), and one O(4) atom to form PO4 tetrahedra that share corners with three equivalent Co(1)O6 octahedra and  a cornercorner with one P(1)O4 tetrahedra. The corner-sharing octahedral tilt angles range from 25-70°. There are four inequivalent O sites. In the first O site, O(1) is bonded in a distorted trigonal planar geometry to one Li(1), one Co(1), and one P(1) atom. In the second O site, O(2) is bonded to two equivalent Li(1), one Co(1), and one P(1) atom to form distorted OLi2CoP trigonal pyramids that share corners with three equivalent O(2)Li2CoP trigonal pyramids and corners with three equivalent O(4)Li2P2 trigonal pyramids. In the third O site, O(3) is bonded in a 3-coordinate geometry to one Li(1), one Co(1), and one P(1) atom. In the fourth O site, O(4) is bonded to two equivalent Li(1) and two equivalent P(1) atoms to form distorted corner-sharing OLi2P2 trigonal pyramids.
Li2CoP2O7 crystallizes in the monoclinic C2/c space group. Li(1) is bonded in a 5-coordinate geometry to one O(1), one O(3), one O(4), and two equivalent O(2) atoms. The Li(1)-O(1) bond length is 1.97 Å. The Li(1)-O(3) bond length is 2.48 Å. The Li(1)-O(4) bond length is 2.45 Å. There is one shorter (2.11 Å) and one longer (2.41 Å) Li(1)-O(2) bond length. Co(1) is bonded to two equivalent O(1), two equivalent O(2), and two equivalent O(3) atoms to form CoO6 octahedra that share corners with six equivalent P(1)O4 tetrahedra. Both Co(1)-O(1) bond lengths are 2.08 Å. Both Co(1)-O(2) bond lengths are 2.26 Å. Both Co(1)-O(3) bond lengths are 2.02 Å. P(1) is bonded to one O(1), one O(2), one O(3), and one O(4) atom to form PO4 tetrahedra that share corners with three equivalent Co(1)O6 octahedra and  a cornercorner with one P(1)O4 tetrahedra. The corner-sharing octahedral tilt angles range from 25-70°. The P(1)-O(1) bond length is 1.52 Å. The P(1)-O(2) bond length is 1.54 Å. The P(1)-O(3) bond length is 1.50 Å. The P(1)-O(4) bond length is 1.69 Å. There are four inequivalent O sites. In the first O site, O(1) is bonded in a distorted trigonal planar geometry to one Li(1), one Co(1), and one P(1) atom. In the second O site, O(2) is bonded to two equivalent Li(1), one Co(1), and one P(1) atom to form distorted OLi2CoP trigonal pyramids that share corners with three equivalent O(2)Li2CoP trigonal pyramids and corners with three equivalent O(4)Li2P2 trigonal pyramids. In the third O site, O(3) is bonded in a 3-coordinate geometry to one Li(1), one Co(1), and one P(1) atom. In the fourth O site, O(4) is bonded to two equivalent Li(1) and two equivalent P(1) atoms to form distorted corner-sharing OLi2P2 trigonal pyramids.