Co2P2O7 crystallizes in the triclinic P1 space group. There are four inequivalent Co sites. In the first Co site, Co(1) is bonded to one O(10), one O(12), one O(14), one O(4), one O(6), and one O(8) atom to form distorted CoO6 octahedra that share  a cornercorner with one P(1)O4 tetrahedra,  a cornercorner with one P(3)O4 tetrahedra, corners with two equivalent P(2)O4 tetrahedra, corners with two equivalent P(4)O4 tetrahedra, and edges with three equivalent Co(4)O6 octahedra. In the second Co site, Co(2) is bonded to one O(11), one O(13), one O(3), one O(5), one O(7), and one O(9) atom to form distorted CoO6 octahedra that share  a cornercorner with one P(2)O4 tetrahedra,  a cornercorner with one P(4)O4 tetrahedra, corners with two equivalent P(1)O4 tetrahedra, corners with two equivalent P(3)O4 tetrahedra, and edges with three equivalent Co(3)O6 octahedra. In the third Co site, Co(3) is bonded to one O(11), one O(13), one O(3), one O(5), one O(7), and one O(9) atom to form distorted CoO6 octahedra that share  a cornercorner with one P(2)O4 tetrahedra,  a cornercorner with one P(4)O4 tetrahedra, corners with two equivalent P(1)O4 tetrahedra, corners with two equivalent P(3)O4 tetrahedra, and edges with three equivalent Co(2)O6 octahedra. In the fourth Co site, Co(4) is bonded to one O(10), one O(12), one O(14), one O(4), one O(6), and one O(8) atom to form distorted CoO6 octahedra that share  a cornercorner with one P(1)O4 tetrahedra,  a cornercorner with one P(3)O4 tetrahedra, corners with two equivalent P(2)O4 tetrahedra, corners with two equivalent P(4)O4 tetrahedra, and edges with three equivalent Co(1)O6 octahedra. There are four inequivalent P sites. In the first P site, P(1) is bonded to one O(11), one O(2), one O(6), and one O(9) atom to form PO4 tetrahedra that share  a cornercorner with one Co(1)O6 octahedra,  a cornercorner with one Co(4)O6 octahedra, corners with two equivalent Co(2)O6 octahedra, corners with two equivalent Co(3)O6 octahedra, and  a cornercorner with one P(4)O4 tetrahedra. The corner-sharing octahedral tilt angles range from 46-62°. In the second P site, P(2) is bonded to one O(1), one O(10), one O(12), and one O(5) atom to form PO4 tetrahedra that share  a cornercorner with one Co(2)O6 octahedra,  a cornercorner with one Co(3)O6 octahedra, corners with two equivalent Co(1)O6 octahedra, corners with two equivalent Co(4)O6 octahedra, and  a cornercorner with one P(3)O4 tetrahedra. The corner-sharing octahedral tilt angles range from 46-61°. In the third P site, P(3) is bonded to one O(1), one O(13), one O(4), and one O(7) atom to form PO4 tetrahedra that share  a cornercorner with one Co(1)O6 octahedra,  a cornercorner with one Co(4)O6 octahedra, corners with two equivalent Co(2)O6 octahedra, corners with two equivalent Co(3)O6 octahedra, and  a cornercorner with one P(2)O4 tetrahedra. The corner-sharing octahedral tilt angles range from 46-61°. In the fourth P site, P(4) is bonded to one O(14), one O(2), one O(3), and one O(8) atom to form PO4 tetrahedra that share  a cornercorner with one Co(2)O6 octahedra,  a cornercorner with one Co(3)O6 octahedra, corners with two equivalent Co(1)O6 octahedra, corners with two equivalent Co(4)O6 octahedra, and  a cornercorner with one P(1)O4 tetrahedra. The corner-sharing octahedral tilt angles range from 46-62°. There are fourteen inequivalent O sites. In the first O site, O(1) is bonded in a linear geometry to one P(2) and one P(3) atom. In the second O site, O(2) is bonded in a linear geometry to one P(1) and one P(4) atom. In the third O site, O(3) is bonded in a distorted trigonal planar geometry to one Co(2), one Co(3), and one P(4) atom. In the fourth O site, O(4) is bonded in a distorted trigonal planar geometry to one Co(1), one Co(4), and one P(3) atom. In the fifth O site, O(5) is bonded in a distorted trigonal planar geometry to one Co(2), one Co(3), and one P(2) atom. In the sixth O site, O(6) is bonded in a distorted trigonal planar geometry to one Co(1), one Co(4), and one P(1) atom. In the seventh O site, O(7) is bonded in a 3-coordinate geometry to one Co(2), one Co(3), and one P(3) atom. In the eighth O site, O(8) is bonded in a 3-coordinate geometry to one Co(1), one Co(4), and one P(4) atom. In the ninth O site, O(9) is bonded in a 3-coordinate geometry to one Co(2), one Co(3), and one P(1) atom. In the tenth O site, O(10) is bonded in a 3-coordinate geometry to one Co(1), one Co(4), and one P(2) atom. In the eleventh O site, O(11) is bonded in a 3-coordinate geometry to one Co(2), one Co(3), and one P(1) atom. In the twelfth O site, O(12) is bonded in a 3-coordinate geometry to one Co(1), one Co(4), and one P(2) atom. In the thirteenth O site, O(13) is bonded in a 3-coordinate geometry to one Co(2), one Co(3), and one P(3) atom. In the fourteenth O site, O(14) is bonded in a 3-coordinate geometry to one Co(1), one Co(4), and one P(4) atom.
Co2P2O7 crystallizes in the triclinic P1 space group. There are four inequivalent Co sites. In the first Co site, Co(1) is bonded to one O(10), one O(12), one O(14), one O(4), one O(6), and one O(8) atom to form distorted CoO6 octahedra that share  a cornercorner with one P(1)O4 tetrahedra,  a cornercorner with one P(3)O4 tetrahedra, corners with two equivalent P(2)O4 tetrahedra, corners with two equivalent P(4)O4 tetrahedra, and edges with three equivalent Co(4)O6 octahedra. The Co(1)-O(10) bond length is 2.28 Å. The Co(1)-O(12) bond length is 2.08 Å. The Co(1)-O(14) bond length is 2.08 Å. The Co(1)-O(4) bond length is 2.10 Å. The Co(1)-O(6) bond length is 2.09 Å. The Co(1)-O(8) bond length is 2.30 Å. In the second Co site, Co(2) is bonded to one O(11), one O(13), one O(3), one O(5), one O(7), and one O(9) atom to form distorted CoO6 octahedra that share  a cornercorner with one P(2)O4 tetrahedra,  a cornercorner with one P(4)O4 tetrahedra, corners with two equivalent P(1)O4 tetrahedra, corners with two equivalent P(3)O4 tetrahedra, and edges with three equivalent Co(3)O6 octahedra. The Co(2)-O(11) bond length is 2.30 Å. The Co(2)-O(13) bond length is 2.28 Å. The Co(2)-O(3) bond length is 2.09 Å. The Co(2)-O(5) bond length is 2.10 Å. The Co(2)-O(7) bond length is 2.07 Å. The Co(2)-O(9) bond length is 2.08 Å. In the third Co site, Co(3) is bonded to one O(11), one O(13), one O(3), one O(5), one O(7), and one O(9) atom to form distorted CoO6 octahedra that share  a cornercorner with one P(2)O4 tetrahedra,  a cornercorner with one P(4)O4 tetrahedra, corners with two equivalent P(1)O4 tetrahedra, corners with two equivalent P(3)O4 tetrahedra, and edges with three equivalent Co(2)O6 octahedra. The Co(3)-O(11) bond length is 2.08 Å. The Co(3)-O(13) bond length is 2.10 Å. The Co(3)-O(3) bond length is 2.09 Å. The Co(3)-O(5) bond length is 2.09 Å. The Co(3)-O(7) bond length is 2.28 Å. The Co(3)-O(9) bond length is 2.28 Å. In the fourth Co site, Co(4) is bonded to one O(10), one O(12), one O(14), one O(4), one O(6), and one O(8) atom to form distorted CoO6 octahedra that share  a cornercorner with one P(1)O4 tetrahedra,  a cornercorner with one P(3)O4 tetrahedra, corners with two equivalent P(2)O4 tetrahedra, corners with two equivalent P(4)O4 tetrahedra, and edges with three equivalent Co(1)O6 octahedra. The Co(4)-O(10) bond length is 2.10 Å. The Co(4)-O(12) bond length is 2.28 Å. The Co(4)-O(14) bond length is 2.28 Å. The Co(4)-O(4) bond length is 2.09 Å. The Co(4)-O(6) bond length is 2.09 Å. The Co(4)-O(8) bond length is 2.09 Å. There are four inequivalent P sites. In the first P site, P(1) is bonded to one O(11), one O(2), one O(6), and one O(9) atom to form PO4 tetrahedra that share  a cornercorner with one Co(1)O6 octahedra,  a cornercorner with one Co(4)O6 octahedra, corners with two equivalent Co(2)O6 octahedra, corners with two equivalent Co(3)O6 octahedra, and  a cornercorner with one P(4)O4 tetrahedra. The corner-sharing octahedral tilt angles range from 46-62°. The P(1)-O(11) bond length is 1.54 Å. The P(1)-O(2) bond length is 1.58 Å. The P(1)-O(6) bond length is 1.54 Å. The P(1)-O(9) bond length is 1.54 Å. In the second P site, P(2) is bonded to one O(1), one O(10), one O(12), and one O(5) atom to form PO4 tetrahedra that share  a cornercorner with one Co(2)O6 octahedra,  a cornercorner with one Co(3)O6 octahedra, corners with two equivalent Co(1)O6 octahedra, corners with two equivalent Co(4)O6 octahedra, and  a cornercorner with one P(3)O4 tetrahedra. The corner-sharing octahedral tilt angles range from 46-61°. The P(2)-O(1) bond length is 1.58 Å. The P(2)-O(10) bond length is 1.54 Å. The P(2)-O(12) bond length is 1.54 Å. The P(2)-O(5) bond length is 1.54 Å. In the third P site, P(3) is bonded to one O(1), one O(13), one O(4), and one O(7) atom to form PO4 tetrahedra that share  a cornercorner with one Co(1)O6 octahedra,  a cornercorner with one Co(4)O6 octahedra, corners with two equivalent Co(2)O6 octahedra, corners with two equivalent Co(3)O6 octahedra, and  a cornercorner with one P(2)O4 tetrahedra. The corner-sharing octahedral tilt angles range from 46-61°. The P(3)-O(1) bond length is 1.58 Å. The P(3)-O(13) bond length is 1.54 Å. The P(3)-O(4) bond length is 1.54 Å. The P(3)-O(7) bond length is 1.54 Å. In the fourth P site, P(4) is bonded to one O(14), one O(2), one O(3), and one O(8) atom to form PO4 tetrahedra that share  a cornercorner with one Co(2)O6 octahedra,  a cornercorner with one Co(3)O6 octahedra, corners with two equivalent Co(1)O6 octahedra, corners with two equivalent Co(4)O6 octahedra, and  a cornercorner with one P(1)O4 tetrahedra. The corner-sharing octahedral tilt angles range from 46-62°. The P(4)-O(14) bond length is 1.54 Å. The P(4)-O(2) bond length is 1.58 Å. The P(4)-O(3) bond length is 1.54 Å. The P(4)-O(8) bond length is 1.54 Å. There are fourteen inequivalent O sites. In the first O site, O(1) is bonded in a linear geometry to one P(2) and one P(3) atom. In the second O site, O(2) is bonded in a linear geometry to one P(1) and one P(4) atom. In the third O site, O(3) is bonded in a distorted trigonal planar geometry to one Co(2), one Co(3), and one P(4) atom. In the fourth O site, O(4) is bonded in a distorted trigonal planar geometry to one Co(1), one Co(4), and one P(3) atom. In the fifth O site, O(5) is bonded in a distorted trigonal planar geometry to one Co(2), one Co(3), and one P(2) atom. In the sixth O site, O(6) is bonded in a distorted trigonal planar geometry to one Co(1), one Co(4), and one P(1) atom. In the seventh O site, O(7) is bonded in a 3-coordinate geometry to one Co(2), one Co(3), and one P(3) atom. In the eighth O site, O(8) is bonded in a 3-coordinate geometry to one Co(1), one Co(4), and one P(4) atom. In the ninth O site, O(9) is bonded in a 3-coordinate geometry to one Co(2), one Co(3), and one P(1) atom. In the tenth O site, O(10) is bonded in a 3-coordinate geometry to one Co(1), one Co(4), and one P(2) atom. In the eleventh O site, O(11) is bonded in a 3-coordinate geometry to one Co(2), one Co(3), and one P(1) atom. In the twelfth O site, O(12) is bonded in a 3-coordinate geometry to one Co(1), one Co(4), and one P(2) atom. In the thirteenth O site, O(13) is bonded in a 3-coordinate geometry to one Co(2), one Co(3), and one P(3) atom. In the fourteenth O site, O(14) is bonded in a 3-coordinate geometry to one Co(1), one Co(4), and one P(4) atom.