K2CuCPO7 crystallizes in the monoclinic P2_1/m space group. K(1) is bonded to one O(1), one O(2), one O(3), one O(5), one O(6), and two equivalent O(4) atoms to form distorted KO7 pentagonal bipyramids that share corners with two equivalent K(1)O7 pentagonal bipyramids, corners with two equivalent P(1)O4 tetrahedra,  an edgeedge with one K(1)O7 pentagonal bipyramid,  an edgeedge with one P(1)O4 tetrahedra, and  a faceface with one K(1)O7 pentagonal bipyramid. Cu(1) is bonded in a distorted rectangular see-saw-like geometry to one O(2), one O(3), one O(5), and one O(6) atom. C(1) is bonded in a trigonal planar geometry to one O(1), one O(2), and one O(3) atom. P(1) is bonded to one O(5), one O(6), and two equivalent O(4) atoms to form PO4 tetrahedra that share corners with four equivalent K(1)O7 pentagonal bipyramids and edges with two equivalent K(1)O7 pentagonal bipyramids. There are six inequivalent O sites. In the first O site, O(1) is bonded in a 3-coordinate geometry to two equivalent K(1) and one C(1) atom. In the second O site, O(2) is bonded to two equivalent K(1), one Cu(1), and one C(1) atom to form distorted edge-sharing OK2CuC trigonal pyramids. In the third O site, O(3) is bonded to two equivalent K(1), one Cu(1), and one C(1) atom to form distorted edge-sharing OK2CuC trigonal pyramids. In the fourth O site, O(4) is bonded in a distorted single-bond geometry to two equivalent K(1) and one P(1) atom. In the fifth O site, O(5) is bonded in a 4-coordinate geometry to two equivalent K(1), one Cu(1), and one P(1) atom. In the sixth O site, O(6) is bonded in a distorted bent 150 degrees geometry to two equivalent K(1), one Cu(1), and one P(1) atom.
K2CuCPO7 crystallizes in the monoclinic P2_1/m space group. K(1) is bonded to one O(1), one O(2), one O(3), one O(5), one O(6), and two equivalent O(4) atoms to form distorted KO7 pentagonal bipyramids that share corners with two equivalent K(1)O7 pentagonal bipyramids, corners with two equivalent P(1)O4 tetrahedra,  an edgeedge with one K(1)O7 pentagonal bipyramid,  an edgeedge with one P(1)O4 tetrahedra, and  a faceface with one K(1)O7 pentagonal bipyramid. The K(1)-O(1) bond length is 2.69 Å. The K(1)-O(2) bond length is 2.76 Å. The K(1)-O(3) bond length is 2.70 Å. The K(1)-O(5) bond length is 2.78 Å. The K(1)-O(6) bond length is 2.90 Å. There is one shorter (2.72 Å) and one longer (2.84 Å) K(1)-O(4) bond length. Cu(1) is bonded in a distorted rectangular see-saw-like geometry to one O(2), one O(3), one O(5), and one O(6) atom. The Cu(1)-O(2) bond length is 1.91 Å. The Cu(1)-O(3) bond length is 1.99 Å. The Cu(1)-O(5) bond length is 1.95 Å. The Cu(1)-O(6) bond length is 1.86 Å. C(1) is bonded in a trigonal planar geometry to one O(1), one O(2), and one O(3) atom. The C(1)-O(1) bond length is 1.24 Å. The C(1)-O(2) bond length is 1.31 Å. The C(1)-O(3) bond length is 1.31 Å. P(1) is bonded to one O(5), one O(6), and two equivalent O(4) atoms to form PO4 tetrahedra that share corners with four equivalent K(1)O7 pentagonal bipyramids and edges with two equivalent K(1)O7 pentagonal bipyramids. The P(1)-O(5) bond length is 1.58 Å. The P(1)-O(6) bond length is 1.61 Å. Both P(1)-O(4) bond lengths are 1.53 Å. There are six inequivalent O sites. In the first O site, O(1) is bonded in a 3-coordinate geometry to two equivalent K(1) and one C(1) atom. In the second O site, O(2) is bonded to two equivalent K(1), one Cu(1), and one C(1) atom to form distorted edge-sharing OK2CuC trigonal pyramids. In the third O site, O(3) is bonded to two equivalent K(1), one Cu(1), and one C(1) atom to form distorted edge-sharing OK2CuC trigonal pyramids. In the fourth O site, O(4) is bonded in a distorted single-bond geometry to two equivalent K(1) and one P(1) atom. In the fifth O site, O(5) is bonded in a 4-coordinate geometry to two equivalent K(1), one Cu(1), and one P(1) atom. In the sixth O site, O(6) is bonded in a distorted bent 150 degrees geometry to two equivalent K(1), one Cu(1), and one P(1) atom.