CrP2O7 crystallizes in the monoclinic P2_1/c space group. Cr(1) is bonded to one O(1), one O(3), one O(4), one O(5), one O(6), and one O(7) atom to form CrO6 octahedra that share  a cornercorner with one P(1)O4 tetrahedra, corners with three equivalent P(2)O4 tetrahedra, and  an edgeedge with one P(1)O4 tetrahedra. 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(7) atom to form PO4 tetrahedra that share  a cornercorner with one Cr(1)O6 octahedra,  a cornercorner with one P(2)O4 tetrahedra, and  an edgeedge with one Cr(1)O6 octahedra. The corner-sharing octahedral tilt angles are 30°. In the second P site, P(2) is bonded to one O(1), one O(2), one O(5), and one O(6) atom to form PO4 tetrahedra that share corners with three equivalent Cr(1)O6 octahedra and  a cornercorner with one P(1)O4 tetrahedra. The corner-sharing octahedral tilt angles range from 37-43°. There are seven inequivalent O sites. In the first O site, O(1) is bonded in a bent 150 degrees geometry to one Cr(1) and one P(2) atom. In the second O site, O(2) is bonded in a bent 150 degrees geometry to one P(1) and one P(2) atom. In the third O site, O(3) is bonded in a bent 150 degrees geometry to one Cr(1) and one P(1) atom. In the fourth O site, O(4) is bonded in an L-shaped geometry to one Cr(1) and one P(1) atom. In the fifth O site, O(5) is bonded in a bent 150 degrees geometry to one Cr(1) and one P(2) atom. In the sixth O site, O(6) is bonded in a bent 150 degrees geometry to one Cr(1) and one P(2) atom. In the seventh O site, O(7) is bonded in an L-shaped geometry to one Cr(1) and one P(1) atom.
CrP2O7 crystallizes in the monoclinic P2_1/c space group. Cr(1) is bonded to one O(1), one O(3), one O(4), one O(5), one O(6), and one O(7) atom to form CrO6 octahedra that share  a cornercorner with one P(1)O4 tetrahedra, corners with three equivalent P(2)O4 tetrahedra, and  an edgeedge with one P(1)O4 tetrahedra. The Cr(1)-O(1) bond length is 1.94 Å. The Cr(1)-O(3) bond length is 1.91 Å. The Cr(1)-O(4) bond length is 1.95 Å. The Cr(1)-O(5) bond length is 1.97 Å. The Cr(1)-O(6) bond length is 1.93 Å. The Cr(1)-O(7) bond length is 1.99 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(7) atom to form PO4 tetrahedra that share  a cornercorner with one Cr(1)O6 octahedra,  a cornercorner with one P(2)O4 tetrahedra, and  an edgeedge with one Cr(1)O6 octahedra. The corner-sharing octahedral tilt angles are 30°. The P(1)-O(2) bond length is 1.58 Å. The P(1)-O(3) bond length is 1.51 Å. The P(1)-O(4) bond length is 1.56 Å. The P(1)-O(7) bond length is 1.54 Å. In the second P site, P(2) is bonded to one O(1), one O(2), one O(5), and one O(6) atom to form PO4 tetrahedra that share corners with three equivalent Cr(1)O6 octahedra and  a cornercorner with one P(1)O4 tetrahedra. The corner-sharing octahedral tilt angles range from 37-43°. The P(2)-O(1) bond length is 1.53 Å. The P(2)-O(2) bond length is 1.63 Å. The P(2)-O(5) bond length is 1.51 Å. The P(2)-O(6) bond length is 1.53 Å. There are seven inequivalent O sites. In the first O site, O(1) is bonded in a bent 150 degrees geometry to one Cr(1) and one P(2) atom. In the second O site, O(2) is bonded in a bent 150 degrees geometry to one P(1) and one P(2) atom. In the third O site, O(3) is bonded in a bent 150 degrees geometry to one Cr(1) and one P(1) atom. In the fourth O site, O(4) is bonded in an L-shaped geometry to one Cr(1) and one P(1) atom. In the fifth O site, O(5) is bonded in a bent 150 degrees geometry to one Cr(1) and one P(2) atom. In the sixth O site, O(6) is bonded in a bent 150 degrees geometry to one Cr(1) and one P(2) atom. In the seventh O site, O(7) is bonded in an L-shaped geometry to one Cr(1) and one P(1) atom.