CaCuP2O7 crystallizes in the triclinic P-1 space group. Ca(1) is bonded in a 7-coordinate geometry to one O(1), one O(3), one O(7), two equivalent O(4), and two equivalent O(5) atoms. Cu(1) is bonded to one O(1), one O(2), one O(3), one O(5), and one O(7) atom to form distorted CuO5 square pyramids that share corners with two equivalent P(2)O4 tetrahedra and corners with three equivalent P(1)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(3), and one O(6) atom to form PO4 tetrahedra that share corners with three equivalent Cu(1)O5 square pyramids and  a cornercorner with one P(2)O4 tetrahedra. In the second P site, P(2) is bonded to one O(4), one O(5), one O(6), and one O(7) atom to form PO4 tetrahedra that share corners with two equivalent Cu(1)O5 square pyramids and  a cornercorner with one P(1)O4 tetrahedra. There are seven inequivalent O sites. In the first O site, O(1) is bonded in a distorted trigonal planar geometry to one Ca(1), one Cu(1), and one P(1) atom. In the second O site, O(2) is bonded in a bent 150 degrees geometry to one Cu(1) and one P(1) atom. In the third O site, O(3) is bonded in a 3-coordinate geometry to one Ca(1), one Cu(1), and one P(1) atom. In the fourth O site, O(4) is bonded in a distorted trigonal planar geometry to two equivalent Ca(1) and one P(2) atom. In the fifth O site, O(5) is bonded in a 4-coordinate geometry to two equivalent Ca(1), one Cu(1), and one P(2) atom. In the sixth O site, O(6) is bonded in a bent 150 degrees geometry to one P(1) and one P(2) atom. In the seventh O site, O(7) is bonded in a distorted trigonal non-coplanar geometry to one Ca(1), one Cu(1), and one P(2) atom.
CaCuP2O7 crystallizes in the triclinic P-1 space group. Ca(1) is bonded in a 7-coordinate geometry to one O(1), one O(3), one O(7), two equivalent O(4), and two equivalent O(5) atoms. The Ca(1)-O(1) bond length is 2.51 Å. The Ca(1)-O(3) bond length is 2.58 Å. The Ca(1)-O(7) bond length is 2.36 Å. There is one shorter (2.31 Å) and one longer (2.41 Å) Ca(1)-O(4) bond length. There is one shorter (2.39 Å) and one longer (2.76 Å) Ca(1)-O(5) bond length. Cu(1) is bonded to one O(1), one O(2), one O(3), one O(5), and one O(7) atom to form distorted CuO5 square pyramids that share corners with two equivalent P(2)O4 tetrahedra and corners with three equivalent P(1)O4 tetrahedra. The Cu(1)-O(1) bond length is 1.94 Å. The Cu(1)-O(2) bond length is 2.00 Å. The Cu(1)-O(3) bond length is 2.09 Å. The Cu(1)-O(5) bond length is 2.55 Å. The Cu(1)-O(7) bond length is 1.94 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(3), and one O(6) atom to form PO4 tetrahedra that share corners with three equivalent Cu(1)O5 square pyramids and  a cornercorner with one P(2)O4 tetrahedra. The P(1)-O(1) bond length is 1.55 Å. The P(1)-O(2) bond length is 1.52 Å. The P(1)-O(3) bond length is 1.54 Å. The P(1)-O(6) bond length is 1.62 Å. In the second P site, P(2) is bonded to one O(4), one O(5), one O(6), and one O(7) atom to form PO4 tetrahedra that share corners with two equivalent Cu(1)O5 square pyramids and  a cornercorner with one P(1)O4 tetrahedra. The P(2)-O(4) bond length is 1.52 Å. The P(2)-O(5) bond length is 1.52 Å. The P(2)-O(6) bond length is 1.62 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 distorted trigonal planar geometry to one Ca(1), one Cu(1), and one P(1) atom. In the second O site, O(2) is bonded in a bent 150 degrees geometry to one Cu(1) and one P(1) atom. In the third O site, O(3) is bonded in a 3-coordinate geometry to one Ca(1), one Cu(1), and one P(1) atom. In the fourth O site, O(4) is bonded in a distorted trigonal planar geometry to two equivalent Ca(1) and one P(2) atom. In the fifth O site, O(5) is bonded in a 4-coordinate geometry to two equivalent Ca(1), one Cu(1), and one P(2) atom. In the sixth O site, O(6) is bonded in a bent 150 degrees geometry to one P(1) and one P(2) atom. In the seventh O site, O(7) is bonded in a distorted trigonal non-coplanar geometry to one Ca(1), one Cu(1), and one P(2) atom.