CaCuP2O7 crystallizes in the monoclinic P2_1/c space group. Ca(1) is bonded in a 8-coordinate geometry to one O(1), one O(2), one O(5), one O(6), two equivalent O(3), and two equivalent O(7) atoms. Cu(1) is bonded to one O(1), one O(2), one O(5), one O(6), and one O(7) atom to form distorted CuO5 trigonal bipyramids 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(4), and one O(6) atom to form PO4 tetrahedra that share  a cornercorner with one P(2)O4 tetrahedra and corners with three equivalent Cu(1)O5 trigonal bipyramids. In the second P site, P(2) is bonded to one O(3), one O(4), one O(5), and one O(7) atom to form PO4 tetrahedra that share  a cornercorner with one P(1)O4 tetrahedra and corners with two equivalent Cu(1)O5 trigonal bipyramids. There are seven inequivalent O sites. In the first O site, O(5) is bonded in a 3-coordinate geometry to one Ca(1), one Cu(1), and one P(2) atom. In the second O site, O(6) is bonded in a distorted trigonal planar geometry to one Ca(1), one Cu(1), and one P(1) atom. In the third O site, O(7) is bonded in a 3-coordinate geometry to two equivalent Ca(1), one Cu(1), and one P(2) atom. In the fourth O site, O(1) is bonded in a distorted single-bond geometry to one Ca(1), one Cu(1), and one P(1) atom. In the fifth O site, O(2) is bonded in a distorted trigonal planar geometry to one Ca(1), one Cu(1), and one P(1) atom. In the sixth O site, O(3) is bonded in a distorted trigonal planar geometry to two equivalent Ca(1) and one P(2) atom. In the seventh O site, O(4) is bonded in a bent 120 degrees geometry to one P(1) and one P(2) atom.
CaCuP2O7 crystallizes in the monoclinic P2_1/c space group. Ca(1) is bonded in a 8-coordinate geometry to one O(1), one O(2), one O(5), one O(6), two equivalent O(3), and two equivalent O(7) atoms. The Ca(1)-O(1) bond length is 2.47 Å. The Ca(1)-O(2) bond length is 2.62 Å. The Ca(1)-O(5) bond length is 2.49 Å. The Ca(1)-O(6) bond length is 2.49 Å. There is one shorter (2.40 Å) and one longer (2.45 Å) Ca(1)-O(3) bond length. There is one shorter (2.44 Å) and one longer (2.86 Å) Ca(1)-O(7) bond length. Cu(1) is bonded to one O(1), one O(2), one O(5), one O(6), and one O(7) atom to form distorted CuO5 trigonal bipyramids 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 2.23 Å. The Cu(1)-O(2) bond length is 1.99 Å. The Cu(1)-O(5) bond length is 1.92 Å. The Cu(1)-O(6) bond length is 1.97 Å. The Cu(1)-O(7) bond length is 2.03 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  a cornercorner with one P(2)O4 tetrahedra and corners with three equivalent Cu(1)O5 trigonal bipyramids. The P(1)-O(1) bond length is 1.50 Å. The P(1)-O(2) bond length is 1.54 Å. The P(1)-O(4) bond length is 1.61 Å. The P(1)-O(6) bond length is 1.54 Å. In the second P site, P(2) is bonded to one O(3), one O(4), one O(5), and one O(7) atom to form PO4 tetrahedra that share  a cornercorner with one P(1)O4 tetrahedra and corners with two equivalent Cu(1)O5 trigonal bipyramids. The P(2)-O(3) bond length is 1.51 Å. The P(2)-O(4) bond length is 1.59 Å. The P(2)-O(5) bond length is 1.51 Å. The P(2)-O(7) bond length is 1.53 Å. There are seven inequivalent O sites. In the first O site, O(5) is bonded in a 3-coordinate geometry to one Ca(1), one Cu(1), and one P(2) atom. In the second O site, O(6) is bonded in a distorted trigonal planar geometry to one Ca(1), one Cu(1), and one P(1) atom. In the third O site, O(7) is bonded in a 3-coordinate geometry to two equivalent Ca(1), one Cu(1), and one P(2) atom. In the fourth O site, O(1) is bonded in a distorted single-bond geometry to one Ca(1), one Cu(1), and one P(1) atom. In the fifth O site, O(2) is bonded in a distorted trigonal planar geometry to one Ca(1), one Cu(1), and one P(1) atom. In the sixth O site, O(3) is bonded in a distorted trigonal planar geometry to two equivalent Ca(1) and one P(2) atom. In the seventh O site, O(4) is bonded in a bent 120 degrees geometry to one P(1) and one P(2) atom.