CaCu3(P2O7)2 crystallizes in the monoclinic P2_1/c space group. Ca(1) is bonded in a distorted body-centered cubic geometry to two equivalent O(1), two equivalent O(2), two equivalent O(3), and two equivalent O(5) atoms. There are two inequivalent Cu sites. In the first Cu site, Cu(1) is bonded to one O(2), one O(3), one O(5), one O(6), and two equivalent O(7) atoms to form CuO6 octahedra that share corners with three equivalent P(1)O4 tetrahedra, corners with three equivalent P(2)O4 tetrahedra,  an edgeedge with one Cu(1)O6 octahedra, and  an edgeedge with one Cu(2)O6 octahedra. In the second Cu site, Cu(2) is bonded to two equivalent O(1), two equivalent O(2), and two equivalent O(6) atoms to form CuO6 octahedra that share corners with two equivalent P(1)O4 tetrahedra, corners with four equivalent P(2)O4 tetrahedra, and edges with two equivalent Cu(1)O6 octahedra. There are two inequivalent P sites. In the first P site, P(1) is bonded to one O(2), one O(3), one O(4), and one O(5) atom to form PO4 tetrahedra that share  a cornercorner with one Cu(2)O6 octahedra, corners with three equivalent Cu(1)O6 octahedra, and  a cornercorner with one P(2)O4 tetrahedra. The corner-sharing octahedral tilt angles range from 49-60°. In the second P site, P(2) is bonded to one O(1), one O(4), one O(6), and one O(7) atom to form PO4 tetrahedra that share corners with two equivalent Cu(2)O6 octahedra, corners with three equivalent Cu(1)O6 octahedra, and  a cornercorner with one P(1)O4 tetrahedra. The corner-sharing octahedral tilt angles range from 44-64°. There are seven inequivalent O sites. In the first O site, O(5) is bonded in a 2-coordinate geometry to one Ca(1), one Cu(1), and one P(1) atom. In the second O site, O(6) is bonded in a distorted trigonal planar geometry to one Cu(1), one Cu(2), and one P(2) atom. In the third O site, O(7) is bonded in a 3-coordinate geometry to two equivalent Cu(1) and one P(2) atom. In the fourth O site, O(1) is bonded in a distorted trigonal planar geometry to one Ca(1), one Cu(2), and one P(2) atom. In the fifth O site, O(2) is bonded to one Ca(1), one Cu(1), one Cu(2), and one P(1) atom to form distorted corner-sharing OCaCu2P tetrahedra. In the sixth 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 seventh O site, O(4) is bonded in a bent 150 degrees geometry to one P(1) and one P(2) atom.
CaCu3(P2O7)2 crystallizes in the monoclinic P2_1/c space group. Ca(1) is bonded in a distorted body-centered cubic geometry to two equivalent O(1), two equivalent O(2), two equivalent O(3), and two equivalent O(5) atoms. Both Ca(1)-O(1) bond lengths are 2.54 Å. Both Ca(1)-O(2) bond lengths are 2.40 Å. Both Ca(1)-O(3) bond lengths are 2.69 Å. Both Ca(1)-O(5) bond lengths are 2.83 Å. There are two inequivalent Cu sites. In the first Cu site, Cu(1) is bonded to one O(2), one O(3), one O(5), one O(6), and two equivalent O(7) atoms to form CuO6 octahedra that share corners with three equivalent P(1)O4 tetrahedra, corners with three equivalent P(2)O4 tetrahedra,  an edgeedge with one Cu(1)O6 octahedra, and  an edgeedge with one Cu(2)O6 octahedra. The Cu(1)-O(2) bond length is 2.37 Å. The Cu(1)-O(3) bond length is 2.02 Å. The Cu(1)-O(5) bond length is 2.01 Å. The Cu(1)-O(6) bond length is 2.05 Å. There is one shorter (1.99 Å) and one longer (2.31 Å) Cu(1)-O(7) bond length. In the second Cu site, Cu(2) is bonded to two equivalent O(1), two equivalent O(2), and two equivalent O(6) atoms to form CuO6 octahedra that share corners with two equivalent P(1)O4 tetrahedra, corners with four equivalent P(2)O4 tetrahedra, and edges with two equivalent Cu(1)O6 octahedra. Both Cu(2)-O(1) bond lengths are 2.07 Å. Both Cu(2)-O(2) bond lengths are 2.26 Å. Both Cu(2)-O(6) bond lengths are 2.08 Å. There are two inequivalent P sites. In the first P site, P(1) is bonded to one O(2), one O(3), one O(4), and one O(5) atom to form PO4 tetrahedra that share  a cornercorner with one Cu(2)O6 octahedra, corners with three equivalent Cu(1)O6 octahedra, and  a cornercorner with one P(2)O4 tetrahedra. The corner-sharing octahedral tilt angles range from 49-60°. The P(1)-O(2) bond length is 1.54 Å. The P(1)-O(3) bond length is 1.54 Å. The P(1)-O(4) bond length is 1.62 Å. The P(1)-O(5) bond length is 1.53 Å. In the second P site, P(2) is bonded to one O(1), one O(4), one O(6), and one O(7) atom to form PO4 tetrahedra that share corners with two equivalent Cu(2)O6 octahedra, corners with three equivalent Cu(1)O6 octahedra, and  a cornercorner with one P(1)O4 tetrahedra. The corner-sharing octahedral tilt angles range from 44-64°. The P(2)-O(1) bond length is 1.54 Å. The P(2)-O(4) bond length is 1.61 Å. The P(2)-O(6) bond length is 1.56 Å. The P(2)-O(7) bond length is 1.52 Å. There are seven inequivalent O sites. In the first O site, O(5) is bonded in a 2-coordinate geometry to one Ca(1), one Cu(1), and one P(1) atom. In the second O site, O(6) is bonded in a distorted trigonal planar geometry to one Cu(1), one Cu(2), and one P(2) atom. In the third O site, O(7) is bonded in a 3-coordinate geometry to two equivalent Cu(1) and one P(2) atom. In the fourth O site, O(1) is bonded in a distorted trigonal planar geometry to one Ca(1), one Cu(2), and one P(2) atom. In the fifth O site, O(2) is bonded to one Ca(1), one Cu(1), one Cu(2), and one P(1) atom to form distorted corner-sharing OCaCu2P tetrahedra. In the sixth 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 seventh O site, O(4) is bonded in a bent 150 degrees geometry to one P(1) and one P(2) atom.