Cd2P6O17 crystallizes in the monoclinic P2_1/c space group. Cd(1) is bonded to one O(2), one O(5), one O(7), one O(8), and two equivalent O(1) atoms to form CdO6 octahedra that share  a cornercorner with one P(2)O4 tetrahedra, corners with two equivalent P(3)O4 tetrahedra, corners with three equivalent P(1)O4 tetrahedra, and  an edgeedge with one Cd(1)O6 octahedra. There are three 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(4) atom to form PO4 tetrahedra that share corners with three equivalent Cd(1)O6 octahedra,  a cornercorner with one P(1)O4 tetrahedra, and  a cornercorner with one P(2)O4 tetrahedra. The corner-sharing octahedral tilt angles range from 40-60°. In the second P site, P(2) is bonded to one O(4), one O(5), one O(6), and one O(9) atom to form PO4 tetrahedra that share  a cornercorner with one Cd(1)O6 octahedra,  a cornercorner with one P(1)O4 tetrahedra, and corners with two equivalent P(3)O4 tetrahedra. The corner-sharing octahedral tilt angles are 30°. In the third P site, P(3) is bonded to one O(6), one O(7), one O(8), and one O(9) atom to form PO4 tetrahedra that share corners with two equivalent Cd(1)O6 octahedra and corners with two equivalent P(2)O4 tetrahedra. The corner-sharing octahedral tilt angles range from 12-45°. There are nine inequivalent O sites. In the first O site, O(6) is bonded in a bent 120 degrees geometry to one P(2) and one P(3) atom. In the second O site, O(7) is bonded in a distorted bent 150 degrees geometry to one Cd(1) and one P(3) atom. In the third O site, O(8) is bonded in a distorted linear geometry to one Cd(1) and one P(3) atom. In the fourth O site, O(9) is bonded in a bent 150 degrees geometry to one P(2) and one P(3) atom. In the fifth O site, O(1) is bonded in a distorted trigonal planar geometry to two equivalent Cd(1) and one P(1) atom. In the sixth O site, O(2) is bonded in a distorted bent 150 degrees geometry to one Cd(1) and one P(1) atom. In the seventh O site, O(3) is bonded in a linear geometry to two equivalent P(1) atoms. In the eighth O site, O(4) is bonded in a bent 120 degrees geometry to one P(1) and one P(2) atom. In the ninth O site, O(5) is bonded in a bent 150 degrees geometry to one Cd(1) and one P(2) atom.
Cd2P6O17 crystallizes in the monoclinic P2_1/c space group. Cd(1) is bonded to one O(2), one O(5), one O(7), one O(8), and two equivalent O(1) atoms to form CdO6 octahedra that share  a cornercorner with one P(2)O4 tetrahedra, corners with two equivalent P(3)O4 tetrahedra, corners with three equivalent P(1)O4 tetrahedra, and  an edgeedge with one Cd(1)O6 octahedra. The Cd(1)-O(2) bond length is 2.23 Å. The Cd(1)-O(5) bond length is 2.30 Å. The Cd(1)-O(7) bond length is 2.23 Å. The Cd(1)-O(8) bond length is 2.24 Å. There is one shorter (2.34 Å) and one longer (2.40 Å) Cd(1)-O(1) bond length. There are three 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(4) atom to form PO4 tetrahedra that share corners with three equivalent Cd(1)O6 octahedra,  a cornercorner with one P(1)O4 tetrahedra, and  a cornercorner with one P(2)O4 tetrahedra. The corner-sharing octahedral tilt angles range from 40-60°. The P(1)-O(1) bond length is 1.49 Å. The P(1)-O(2) bond length is 1.47 Å. The P(1)-O(3) bond length is 1.57 Å. The P(1)-O(4) 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(9) atom to form PO4 tetrahedra that share  a cornercorner with one Cd(1)O6 octahedra,  a cornercorner with one P(1)O4 tetrahedra, and corners with two equivalent P(3)O4 tetrahedra. The corner-sharing octahedral tilt angles are 30°. The P(2)-O(4) bond length is 1.57 Å. The P(2)-O(5) bond length is 1.46 Å. The P(2)-O(6) bond length is 1.56 Å. The P(2)-O(9) bond length is 1.56 Å. In the third P site, P(3) is bonded to one O(6), one O(7), one O(8), and one O(9) atom to form PO4 tetrahedra that share corners with two equivalent Cd(1)O6 octahedra and corners with two equivalent P(2)O4 tetrahedra. The corner-sharing octahedral tilt angles range from 12-45°. The P(3)-O(6) bond length is 1.62 Å. The P(3)-O(7) bond length is 1.47 Å. The P(3)-O(8) bond length is 1.47 Å. The P(3)-O(9) bond length is 1.62 Å. There are nine inequivalent O sites. In the first O site, O(6) is bonded in a bent 120 degrees geometry to one P(2) and one P(3) atom. In the second O site, O(7) is bonded in a distorted bent 150 degrees geometry to one Cd(1) and one P(3) atom. In the third O site, O(8) is bonded in a distorted linear geometry to one Cd(1) and one P(3) atom. In the fourth O site, O(9) is bonded in a bent 150 degrees geometry to one P(2) and one P(3) atom. In the fifth O site, O(1) is bonded in a distorted trigonal planar geometry to two equivalent Cd(1) and one P(1) atom. In the sixth O site, O(2) is bonded in a distorted bent 150 degrees geometry to one Cd(1) and one P(1) atom. In the seventh O site, O(3) is bonded in a linear geometry to two equivalent P(1) atoms. In the eighth O site, O(4) is bonded in a bent 120 degrees geometry to one P(1) and one P(2) atom. In the ninth O site, O(5) is bonded in a bent 150 degrees geometry to one Cd(1) and one P(2) atom.