CoP2O7 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(1), one O(2), one O(25), one O(26), one O(28), and one O(3) atom to form CoO6 octahedra that share  a cornercorner with one P(2)O4 tetrahedra,  a cornercorner with one P(5)O4 tetrahedra, corners with two equivalent P(1)O4 tetrahedra, and corners with two equivalent P(8)O4 tetrahedra. In the second Co site, Co(2) is bonded to one O(21), one O(22), one O(23), one O(24), one O(27), and one O(4) atom to form CoO6 octahedra that share  a cornercorner with one P(6)O4 tetrahedra,  a cornercorner with one P(7)O4 tetrahedra, corners with two equivalent P(3)O4 tetrahedra, and corners with two equivalent P(4)O4 tetrahedra. In the third Co site, Co(3) is bonded to one O(10), one O(13), one O(14), one O(15), one O(7), and one O(8) atom to form CoO6 octahedra that share  a cornercorner with one P(3)O4 tetrahedra,  a cornercorner with one P(4)O4 tetrahedra, corners with two equivalent P(6)O4 tetrahedra, and corners with two equivalent P(7)O4 tetrahedra. In the fourth Co site, Co(4) is bonded to one O(11), one O(12), one O(16), one O(19), one O(5), and one O(6) atom to form CoO6 octahedra that share  a cornercorner with one P(1)O4 tetrahedra,  a cornercorner with one P(8)O4 tetrahedra, corners with two equivalent P(2)O4 tetrahedra, and corners with two equivalent P(5)O4 tetrahedra. There are eight inequivalent P sites. In the first P site, P(1) is bonded to one O(1), one O(12), one O(20), and one O(28) atom to form PO4 tetrahedra that share  a cornercorner with one Co(4)O6 octahedra, corners with two equivalent Co(1)O6 octahedra, and  a cornercorner with one P(7)O4 tetrahedra. The corner-sharing octahedral tilt angles range from 14-40°. In the second P site, P(2) is bonded to one O(16), one O(17), one O(19), and one O(25) atom to form PO4 tetrahedra that share  a cornercorner with one 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 16-38°. In the third P site, P(3) is bonded to one O(15), one O(17), one O(23), and one O(24) atom to form PO4 tetrahedra that share  a cornercorner with one Co(3)O6 octahedra, corners with two equivalent Co(2)O6 octahedra, and  a cornercorner with one P(2)O4 tetrahedra. The corner-sharing octahedral tilt angles range from 14-46°. In the fourth P site, P(4) is bonded to one O(18), one O(21), one O(27), and one O(7) atom to form PO4 tetrahedra that share  a cornercorner with one Co(3)O6 octahedra, corners with two equivalent Co(2)O6 octahedra, and  a cornercorner with one P(5)O4 tetrahedra. The corner-sharing octahedral tilt angles range from 12-40°. In the fifth P site, P(5) is bonded to one O(18), one O(26), one O(5), and one O(6) atom to form PO4 tetrahedra that share  a cornercorner with one Co(1)O6 octahedra, corners with two equivalent Co(4)O6 octahedra, and  a cornercorner with one P(4)O4 tetrahedra. The corner-sharing octahedral tilt angles range from 9-47°. In the sixth P site, P(6) is bonded to one O(10), one O(4), one O(8), and one O(9) atom to form PO4 tetrahedra that share  a cornercorner with one Co(2)O6 octahedra, corners with two equivalent Co(3)O6 octahedra, and  a cornercorner with one P(8)O4 tetrahedra. The corner-sharing octahedral tilt angles range from 16-38°. In the seventh P site, P(7) is bonded to one O(13), one O(14), one O(20), and one O(22) atom to form PO4 tetrahedra that share  a cornercorner with one Co(2)O6 octahedra, corners with two equivalent Co(3)O6 octahedra, and  a cornercorner with one P(1)O4 tetrahedra. The corner-sharing octahedral tilt angles range from 8-48°. In the eighth P site, P(8) is bonded to one O(11), one O(2), one O(3), and one O(9) atom to form PO4 tetrahedra that share  a cornercorner with one Co(4)O6 octahedra, corners with two equivalent Co(1)O6 octahedra, and  a cornercorner with one P(6)O4 tetrahedra. The corner-sharing octahedral tilt angles range from 14-47°. There are twenty-eight inequivalent O sites. In the first O site, O(1) is bonded in a linear geometry to one Co(1) and one P(1) atom. In the second O site, O(2) is bonded in a distorted bent 120 degrees geometry to one Co(1) and one P(8) atom. In the third O site, O(3) is bonded in a bent 150 degrees geometry to one Co(1) and one P(8) atom. In the fourth O site, O(4) is bonded in a bent 150 degrees geometry to one Co(2) and one P(6) atom. In the fifth O site, O(5) is bonded in a distorted bent 120 degrees geometry to one Co(4) and one P(5) atom. In the sixth O site, O(6) is bonded in a bent 150 degrees geometry to one Co(4) and one P(5) atom. In the seventh O site, O(7) is bonded in a bent 150 degrees geometry to one Co(3) and one P(4) atom. In the eighth O site, O(8) is bonded in a bent 150 degrees geometry to one Co(3) and one P(6) atom. In the ninth O site, O(9) is bonded in a bent 120 degrees geometry to one P(6) and one P(8) atom. In the tenth O site, O(10) is bonded in a linear geometry to one Co(3) and one P(6) atom. In the eleventh O site, O(11) is bonded in a linear geometry to one Co(4) and one P(8) atom. In the twelfth O site, O(12) is bonded in a bent 150 degrees geometry to one Co(4) and one P(1) atom. In the thirteenth O site, O(13) is bonded in a bent 150 degrees geometry to one Co(3) and one P(7) atom. In the fourteenth O site, O(14) is bonded in a distorted bent 120 degrees geometry to one Co(3) and one P(7) atom. In the fifteenth O site, O(15) is bonded in a linear geometry to one Co(3) and one P(3) atom. In the sixteenth O site, O(16) is bonded in a linear geometry to one Co(4) and one P(2) atom. In the seventeenth O site, O(17) is bonded in a bent 120 degrees geometry to one P(2) and one P(3) atom. In the eighteenth O site, O(18) is bonded in a bent 150 degrees geometry to one P(4) and one P(5) atom. In the nineteenth O site, O(19) is bonded in a bent 150 degrees geometry to one Co(4) and one P(2) atom. In the twentieth O site, O(20) is bonded in a bent 150 degrees geometry to one P(1) and one P(7) atom. In the twenty-first O site, O(21) is bonded in a bent 150 degrees geometry to one Co(2) and one P(4) atom. In the twenty-second O site, O(22) is bonded in a linear geometry to one Co(2) and one P(7) atom. In the twenty-third O site, O(23) is bonded in a distorted bent 120 degrees geometry to one Co(2) and one P(3) atom. In the twenty-fourth O site, O(24) is bonded in a bent 150 degrees geometry to one Co(2) and one P(3) atom. In the twenty-fifth O site, O(25) is bonded in a bent 150 degrees geometry to one Co(1) and one P(2) atom. In the twenty-sixth O site, O(26) is bonded in a linear geometry to one Co(1) and one P(5) atom. In the twenty-seventh O site, O(27) is bonded in a linear geometry to one Co(2) and one P(4) atom. In the twenty-eighth O site, O(28) is bonded in a bent 150 degrees geometry to one Co(1) and one P(1) atom.
CoP2O7 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(1), one O(2), one O(25), one O(26), one O(28), and one O(3) atom to form CoO6 octahedra that share  a cornercorner with one P(2)O4 tetrahedra,  a cornercorner with one P(5)O4 tetrahedra, corners with two equivalent P(1)O4 tetrahedra, and corners with two equivalent P(8)O4 tetrahedra. The Co(1)-O(1) bond length is 1.94 Å. The Co(1)-O(2) bond length is 2.00 Å. The Co(1)-O(25) bond length is 1.94 Å. The Co(1)-O(26) bond length is 1.96 Å. The Co(1)-O(28) bond length is 1.96 Å. The Co(1)-O(3) bond length is 1.96 Å. In the second Co site, Co(2) is bonded to one O(21), one O(22), one O(23), one O(24), one O(27), and one O(4) atom to form CoO6 octahedra that share  a cornercorner with one P(6)O4 tetrahedra,  a cornercorner with one P(7)O4 tetrahedra, corners with two equivalent P(3)O4 tetrahedra, and corners with two equivalent P(4)O4 tetrahedra. The Co(2)-O(21) bond length is 1.95 Å. The Co(2)-O(22) bond length is 1.98 Å. The Co(2)-O(23) bond length is 1.97 Å. The Co(2)-O(24) bond length is 1.93 Å. The Co(2)-O(27) bond length is 1.97 Å. The Co(2)-O(4) bond length is 1.97 Å. In the third Co site, Co(3) is bonded to one O(10), one O(13), one O(14), one O(15), one O(7), and one O(8) atom to form CoO6 octahedra that share  a cornercorner with one P(3)O4 tetrahedra,  a cornercorner with one P(4)O4 tetrahedra, corners with two equivalent P(6)O4 tetrahedra, and corners with two equivalent P(7)O4 tetrahedra. The Co(3)-O(10) bond length is 1.89 Å. The Co(3)-O(13) bond length is 1.90 Å. The Co(3)-O(14) bond length is 1.91 Å. The Co(3)-O(15) bond length is 1.90 Å. The Co(3)-O(7) bond length is 1.89 Å. The Co(3)-O(8) bond length is 1.88 Å. In the fourth Co site, Co(4) is bonded to one O(11), one O(12), one O(16), one O(19), one O(5), and one O(6) atom to form CoO6 octahedra that share  a cornercorner with one P(1)O4 tetrahedra,  a cornercorner with one P(8)O4 tetrahedra, corners with two equivalent P(2)O4 tetrahedra, and corners with two equivalent P(5)O4 tetrahedra. The Co(4)-O(11) bond length is 1.89 Å. The Co(4)-O(12) bond length is 1.90 Å. The Co(4)-O(16) bond length is 1.88 Å. The Co(4)-O(19) bond length is 1.89 Å. The Co(4)-O(5) bond length is 1.91 Å. The Co(4)-O(6) bond length is 1.89 Å. There are eight inequivalent P sites. In the first P site, P(1) is bonded to one O(1), one O(12), one O(20), and one O(28) atom to form PO4 tetrahedra that share  a cornercorner with one Co(4)O6 octahedra, corners with two equivalent Co(1)O6 octahedra, and  a cornercorner with one P(7)O4 tetrahedra. The corner-sharing octahedral tilt angles range from 14-40°. The P(1)-O(1) bond length is 1.52 Å. The P(1)-O(12) bond length is 1.53 Å. The P(1)-O(20) bond length is 1.61 Å. The P(1)-O(28) bond length is 1.52 Å. In the second P site, P(2) is bonded to one O(16), one O(17), one O(19), and one O(25) atom to form PO4 tetrahedra that share  a cornercorner with one 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 16-38°. The P(2)-O(16) bond length is 1.51 Å. The P(2)-O(17) bond length is 1.62 Å. The P(2)-O(19) bond length is 1.54 Å. The P(2)-O(25) bond length is 1.53 Å. In the third P site, P(3) is bonded to one O(15), one O(17), one O(23), and one O(24) atom to form PO4 tetrahedra that share  a cornercorner with one Co(3)O6 octahedra, corners with two equivalent Co(2)O6 octahedra, and  a cornercorner with one P(2)O4 tetrahedra. The corner-sharing octahedral tilt angles range from 14-46°. The P(3)-O(15) bond length is 1.51 Å. The P(3)-O(17) bond length is 1.62 Å. The P(3)-O(23) bond length is 1.53 Å. The P(3)-O(24) bond length is 1.53 Å. In the fourth P site, P(4) is bonded to one O(18), one O(21), one O(27), and one O(7) atom to form PO4 tetrahedra that share  a cornercorner with one Co(3)O6 octahedra, corners with two equivalent Co(2)O6 octahedra, and  a cornercorner with one P(5)O4 tetrahedra. The corner-sharing octahedral tilt angles range from 12-40°. The P(4)-O(18) bond length is 1.61 Å. The P(4)-O(21) bond length is 1.53 Å. The P(4)-O(27) bond length is 1.51 Å. The P(4)-O(7) bond length is 1.54 Å. In the fifth P site, P(5) is bonded to one O(18), one O(26), one O(5), and one O(6) atom to form PO4 tetrahedra that share  a cornercorner with one Co(1)O6 octahedra, corners with two equivalent Co(4)O6 octahedra, and  a cornercorner with one P(4)O4 tetrahedra. The corner-sharing octahedral tilt angles range from 9-47°. The P(5)-O(18) bond length is 1.61 Å. The P(5)-O(26) bond length is 1.51 Å. The P(5)-O(5) bond length is 1.55 Å. The P(5)-O(6) bond length is 1.54 Å. In the sixth P site, P(6) is bonded to one O(10), one O(4), one O(8), and one O(9) atom to form PO4 tetrahedra that share  a cornercorner with one Co(2)O6 octahedra, corners with two equivalent Co(3)O6 octahedra, and  a cornercorner with one P(8)O4 tetrahedra. The corner-sharing octahedral tilt angles range from 16-38°. The P(6)-O(10) bond length is 1.50 Å. The P(6)-O(4) bond length is 1.52 Å. The P(6)-O(8) bond length is 1.55 Å. The P(6)-O(9) bond length is 1.62 Å. In the seventh P site, P(7) is bonded to one O(13), one O(14), one O(20), and one O(22) atom to form PO4 tetrahedra that share  a cornercorner with one Co(2)O6 octahedra, corners with two equivalent Co(3)O6 octahedra, and  a cornercorner with one P(1)O4 tetrahedra. The corner-sharing octahedral tilt angles range from 8-48°. The P(7)-O(13) bond length is 1.53 Å. The P(7)-O(14) bond length is 1.55 Å. The P(7)-O(20) bond length is 1.61 Å. The P(7)-O(22) bond length is 1.50 Å. In the eighth P site, P(8) is bonded to one O(11), one O(2), one O(3), and one O(9) atom to form PO4 tetrahedra that share  a cornercorner with one Co(4)O6 octahedra, corners with two equivalent Co(1)O6 octahedra, and  a cornercorner with one P(6)O4 tetrahedra. The corner-sharing octahedral tilt angles range from 14-47°. The P(8)-O(11) bond length is 1.51 Å. The P(8)-O(2) bond length is 1.53 Å. The P(8)-O(3) bond length is 1.53 Å. The P(8)-O(9) bond length is 1.61 Å. There are twenty-eight inequivalent O sites. In the first O site, O(1) is bonded in a linear geometry to one Co(1) and one P(1) atom. In the second O site, O(2) is bonded in a distorted bent 120 degrees geometry to one Co(1) and one P(8) atom. In the third O site, O(3) is bonded in a bent 150 degrees geometry to one Co(1) and one P(8) atom. In the fourth O site, O(4) is bonded in a bent 150 degrees geometry to one Co(2) and one P(6) atom. In the fifth O site, O(5) is bonded in a distorted bent 120 degrees geometry to one Co(4) and one P(5) atom. In the sixth O site, O(6) is bonded in a bent 150 degrees geometry to one Co(4) and one P(5) atom. In the seventh O site, O(7) is bonded in a bent 150 degrees geometry to one Co(3) and one P(4) atom. In the eighth O site, O(8) is bonded in a bent 150 degrees geometry to one Co(3) and one P(6) atom. In the ninth O site, O(9) is bonded in a bent 120 degrees geometry to one P(6) and one P(8) atom. In the tenth O site, O(10) is bonded in a linear geometry to one Co(3) and one P(6) atom. In the eleventh O site, O(11) is bonded in a linear geometry to one Co(4) and one P(8) atom. In the twelfth O site, O(12) is bonded in a bent 150 degrees geometry to one Co(4) and one P(1) atom. In the thirteenth O site, O(13) is bonded in a bent 150 degrees geometry to one Co(3) and one P(7) atom. In the fourteenth O site, O(14) is bonded in a distorted bent 120 degrees geometry to one Co(3) and one P(7) atom. In the fifteenth O site, O(15) is bonded in a linear geometry to one Co(3) and one P(3) atom. In the sixteenth O site, O(16) is bonded in a linear geometry to one Co(4) and one P(2) atom. In the seventeenth O site, O(17) is bonded in a bent 120 degrees geometry to one P(2) and one P(3) atom. In the eighteenth O site, O(18) is bonded in a bent 150 degrees geometry to one P(4) and one P(5) atom. In the nineteenth O site, O(19) is bonded in a bent 150 degrees geometry to one Co(4) and one P(2) atom. In the twentieth O site, O(20) is bonded in a bent 150 degrees geometry to one P(1) and one P(7) atom. In the twenty-first O site, O(21) is bonded in a bent 150 degrees geometry to one Co(2) and one P(4) atom. In the twenty-second O site, O(22) is bonded in a linear geometry to one Co(2) and one P(7) atom. In the twenty-third O site, O(23) is bonded in a distorted bent 120 degrees geometry to one Co(2) and one P(3) atom. In the twenty-fourth O site, O(24) is bonded in a bent 150 degrees geometry to one Co(2) and one P(3) atom. In the twenty-fifth O site, O(25) is bonded in a bent 150 degrees geometry to one Co(1) and one P(2) atom. In the twenty-sixth O site, O(26) is bonded in a linear geometry to one Co(1) and one P(5) atom. In the twenty-seventh O site, O(27) is bonded in a linear geometry to one Co(2) and one P(4) atom. In the twenty-eighth O site, O(28) is bonded in a bent 150 degrees geometry to one Co(1) and one P(1) atom.