UP2O7 crystallizes in the triclinic P1 space group. There are four inequivalent U sites. In the first U site, U(1) is bonded to one O(12), one O(17), one O(20), one O(25), one O(28), and one O(9) atom to form UO6 octahedra that share  a cornercorner with one P(3)O4 tetrahedra,  a cornercorner with one P(4)O4 tetrahedra,  a cornercorner with one P(5)O4 tetrahedra,  a cornercorner with one P(6)O4 tetrahedra,  a cornercorner with one P(7)O4 tetrahedra, and  a cornercorner with one P(8)O4 tetrahedra. In the second U site, U(2) is bonded to one O(10), one O(13), one O(16), one O(19), one O(4), and one O(7) atom to form UO6 octahedra that share  a cornercorner with one P(1)O4 tetrahedra,  a cornercorner with one P(2)O4 tetrahedra,  a cornercorner with one P(3)O4 tetrahedra,  a cornercorner with one P(4)O4 tetrahedra,  a cornercorner with one P(5)O4 tetrahedra, and  a cornercorner with one P(6)O4 tetrahedra. In the third U site, U(3) is bonded to one O(11), one O(14), one O(23), one O(26), one O(3), and one O(6) atom to form UO6 octahedra that share  a cornercorner with one P(1)O4 tetrahedra,  a cornercorner with one P(2)O4 tetrahedra,  a cornercorner with one P(3)O4 tetrahedra,  a cornercorner with one P(4)O4 tetrahedra,  a cornercorner with one P(7)O4 tetrahedra, and  a cornercorner with one P(8)O4 tetrahedra. In the fourth U site, U(4) is bonded to one O(18), one O(2), one O(21), one O(24), one O(27), and one O(5) atom to form UO6 octahedra that share  a cornercorner with one P(1)O4 tetrahedra,  a cornercorner with one P(2)O4 tetrahedra,  a cornercorner with one P(5)O4 tetrahedra,  a cornercorner with one P(6)O4 tetrahedra,  a cornercorner with one P(7)O4 tetrahedra, and  a cornercorner with one P(8)O4 tetrahedra. There are eight 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  a cornercorner with one U(2)O6 octahedra,  a cornercorner with one U(3)O6 octahedra,  a cornercorner with one U(4)O6 octahedra, and  a cornercorner with one P(2)O4 tetrahedra. The corner-sharing octahedral tilt angles range from 6-18°. In the second P site, P(2) is bonded to one O(1), one O(5), one O(6), and one O(7) atom to form PO4 tetrahedra that share  a cornercorner with one U(2)O6 octahedra,  a cornercorner with one U(3)O6 octahedra,  a cornercorner with one U(4)O6 octahedra, and  a cornercorner with one P(1)O4 tetrahedra. The corner-sharing octahedral tilt angles range from 12-18°. In the third P site, P(3) is bonded to one O(10), one O(11), one O(8), and one O(9) atom to form PO4 tetrahedra that share  a cornercorner with one U(1)O6 octahedra,  a cornercorner with one U(2)O6 octahedra,  a cornercorner with one U(3)O6 octahedra, and  a cornercorner with one P(4)O4 tetrahedra. The corner-sharing octahedral tilt angles range from 18-24°. In the fourth P site, P(4) is bonded to one O(12), one O(13), one O(14), and one O(8) atom to form PO4 tetrahedra that share  a cornercorner with one U(1)O6 octahedra,  a cornercorner with one U(2)O6 octahedra,  a cornercorner with one U(3)O6 octahedra, and  a cornercorner with one P(3)O4 tetrahedra. The corner-sharing octahedral tilt angles range from 4-15°. In the fifth P site, P(5) is bonded to one O(15), one O(16), one O(17), and one O(18) atom to form PO4 tetrahedra that share  a cornercorner with one U(1)O6 octahedra,  a cornercorner with one U(2)O6 octahedra,  a cornercorner with one U(4)O6 octahedra, and  a cornercorner with one P(6)O4 tetrahedra. The corner-sharing octahedral tilt angles range from 9-19°. In the sixth P site, P(6) is bonded to one O(15), one O(19), one O(20), and one O(21) atom to form PO4 tetrahedra that share  a cornercorner with one U(1)O6 octahedra,  a cornercorner with one U(2)O6 octahedra,  a cornercorner with one U(4)O6 octahedra, and  a cornercorner with one P(5)O4 tetrahedra. The corner-sharing octahedral tilt angles range from 12-17°. In the seventh P site, P(7) is bonded to one O(22), one O(23), one O(24), and one O(25) atom to form PO4 tetrahedra that share  a cornercorner with one U(1)O6 octahedra,  a cornercorner with one U(3)O6 octahedra,  a cornercorner with one U(4)O6 octahedra, and  a cornercorner with one P(8)O4 tetrahedra. The corner-sharing octahedral tilt angles range from 11-15°. In the eighth P site, P(8) is bonded to one O(22), one O(26), one O(27), and one O(28) atom to form PO4 tetrahedra that share  a cornercorner with one U(1)O6 octahedra,  a cornercorner with one U(3)O6 octahedra,  a cornercorner with one U(4)O6 octahedra, and  a cornercorner with one P(7)O4 tetrahedra. The corner-sharing octahedral tilt angles range from 10-20°. There are twenty-eight inequivalent O sites. In the first O site, O(1) is bonded in a bent 150 degrees geometry to one P(1) and one P(2) atom. In the second O site, O(2) is bonded in a linear geometry to one U(4) and one P(1) atom. In the third O site, O(3) is bonded in a distorted bent 150 degrees geometry to one U(3) and one P(1) atom. In the fourth O site, O(4) is bonded in a linear geometry to one U(2) and one P(1) atom. In the fifth O site, O(5) is bonded in a distorted linear geometry to one U(4) and one P(2) atom. In the sixth O site, O(6) is bonded in a distorted bent 150 degrees geometry to one U(3) and one P(2) atom. In the seventh O site, O(7) is bonded in a linear geometry to one U(2) and one P(2) atom. In the eighth O site, O(8) is bonded in a bent 150 degrees geometry to one P(3) and one P(4) atom. In the ninth O site, O(9) is bonded in a distorted bent 150 degrees geometry to one U(1) and one P(3) atom. In the tenth O site, O(10) is bonded in a bent 150 degrees geometry to one U(2) and one P(3) atom. In the eleventh O site, O(11) is bonded in a bent 150 degrees geometry to one U(3) and one P(3) atom. In the twelfth O site, O(12) is bonded in a linear geometry to one U(1) and one P(4) atom. In the thirteenth O site, O(13) is bonded in a linear geometry to one U(2) and one P(4) atom. In the fourteenth O site, O(14) is bonded in a distorted linear geometry to one U(3) and one P(4) atom. In the fifteenth O site, O(15) is bonded in a bent 150 degrees geometry to one P(5) and one P(6) atom. In the sixteenth O site, O(16) is bonded in a distorted bent 150 degrees geometry to one U(2) and one P(5) atom. In the seventeenth O site, O(17) is bonded in a linear geometry to one U(1) and one P(5) atom. In the eighteenth O site, O(18) is bonded in a linear geometry to one U(4) and one P(5) atom. In the nineteenth O site, O(19) is bonded in a distorted linear geometry to one U(2) and one P(6) atom. In the twentieth O site, O(20) is bonded in a linear geometry to one U(1) and one P(6) atom. In the twenty-first O site, O(21) is bonded in a linear geometry to one U(4) and one P(6) atom. In the twenty-second O site, O(22) is bonded in a bent 150 degrees geometry to one P(7) and one P(8) atom. In the twenty-third O site, O(23) is bonded in a distorted linear geometry to one U(3) and one P(7) atom. In the twenty-fourth O site, O(24) is bonded in a linear geometry to one U(4) and one P(7) atom. In the twenty-fifth O site, O(25) is bonded in a linear geometry to one U(1) and one P(7) atom. In the twenty-sixth O site, O(26) is bonded in a distorted bent 150 degrees geometry to one U(3) and one P(8) atom. In the twenty-seventh O site, O(27) is bonded in a linear geometry to one U(4) and one P(8) atom. In the twenty-eighth O site, O(28) is bonded in a linear geometry to one U(1) and one P(8) atom.
UP2O7 crystallizes in the triclinic P1 space group. There are four inequivalent U sites. In the first U site, U(1) is bonded to one O(12), one O(17), one O(20), one O(25), one O(28), and one O(9) atom to form UO6 octahedra that share  a cornercorner with one P(3)O4 tetrahedra,  a cornercorner with one P(4)O4 tetrahedra,  a cornercorner with one P(5)O4 tetrahedra,  a cornercorner with one P(6)O4 tetrahedra,  a cornercorner with one P(7)O4 tetrahedra, and  a cornercorner with one P(8)O4 tetrahedra. The U(1)-O(12) bond length is 2.25 Å. The U(1)-O(17) bond length is 2.23 Å. The U(1)-O(20) bond length is 2.24 Å. The U(1)-O(25) bond length is 2.24 Å. The U(1)-O(28) bond length is 2.23 Å. The U(1)-O(9) bond length is 2.20 Å. In the second U site, U(2) is bonded to one O(10), one O(13), one O(16), one O(19), one O(4), and one O(7) atom to form UO6 octahedra that share  a cornercorner with one P(1)O4 tetrahedra,  a cornercorner with one P(2)O4 tetrahedra,  a cornercorner with one P(3)O4 tetrahedra,  a cornercorner with one P(4)O4 tetrahedra,  a cornercorner with one P(5)O4 tetrahedra, and  a cornercorner with one P(6)O4 tetrahedra. The U(2)-O(10) bond length is 2.23 Å. The U(2)-O(13) bond length is 2.26 Å. The U(2)-O(16) bond length is 2.23 Å. The U(2)-O(19) bond length is 2.25 Å. The U(2)-O(4) bond length is 2.25 Å. The U(2)-O(7) bond length is 2.22 Å. In the third U site, U(3) is bonded to one O(11), one O(14), one O(23), one O(26), one O(3), and one O(6) atom to form UO6 octahedra that share  a cornercorner with one P(1)O4 tetrahedra,  a cornercorner with one P(2)O4 tetrahedra,  a cornercorner with one P(3)O4 tetrahedra,  a cornercorner with one P(4)O4 tetrahedra,  a cornercorner with one P(7)O4 tetrahedra, and  a cornercorner with one P(8)O4 tetrahedra. The U(3)-O(11) bond length is 2.24 Å. The U(3)-O(14) bond length is 2.25 Å. The U(3)-O(23) bond length is 2.28 Å. The U(3)-O(26) bond length is 2.21 Å. The U(3)-O(3) bond length is 2.22 Å. The U(3)-O(6) bond length is 2.25 Å. In the fourth U site, U(4) is bonded to one O(18), one O(2), one O(21), one O(24), one O(27), and one O(5) atom to form UO6 octahedra that share  a cornercorner with one P(1)O4 tetrahedra,  a cornercorner with one P(2)O4 tetrahedra,  a cornercorner with one P(5)O4 tetrahedra,  a cornercorner with one P(6)O4 tetrahedra,  a cornercorner with one P(7)O4 tetrahedra, and  a cornercorner with one P(8)O4 tetrahedra. The U(4)-O(18) bond length is 2.24 Å. The U(4)-O(2) bond length is 2.25 Å. The U(4)-O(21) bond length is 2.23 Å. The U(4)-O(24) bond length is 2.23 Å. The U(4)-O(27) bond length is 2.22 Å. The U(4)-O(5) bond length is 2.21 Å. There are eight 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  a cornercorner with one U(2)O6 octahedra,  a cornercorner with one U(3)O6 octahedra,  a cornercorner with one U(4)O6 octahedra, and  a cornercorner with one P(2)O4 tetrahedra. The corner-sharing octahedral tilt angles range from 6-18°. The P(1)-O(1) bond length is 1.58 Å. The P(1)-O(2) bond length is 1.51 Å. The P(1)-O(3) bond length is 1.51 Å. The P(1)-O(4) bond length is 1.51 Å. In the second P site, P(2) is bonded to one O(1), one O(5), one O(6), and one O(7) atom to form PO4 tetrahedra that share  a cornercorner with one U(2)O6 octahedra,  a cornercorner with one U(3)O6 octahedra,  a cornercorner with one U(4)O6 octahedra, and  a cornercorner with one P(1)O4 tetrahedra. The corner-sharing octahedral tilt angles range from 12-18°. The P(2)-O(1) bond length is 1.58 Å. The P(2)-O(5) bond length is 1.51 Å. The P(2)-O(6) bond length is 1.51 Å. The P(2)-O(7) bond length is 1.51 Å. In the third P site, P(3) is bonded to one O(10), one O(11), one O(8), and one O(9) atom to form PO4 tetrahedra that share  a cornercorner with one U(1)O6 octahedra,  a cornercorner with one U(2)O6 octahedra,  a cornercorner with one U(3)O6 octahedra, and  a cornercorner with one P(4)O4 tetrahedra. The corner-sharing octahedral tilt angles range from 18-24°. The P(3)-O(10) bond length is 1.51 Å. The P(3)-O(11) bond length is 1.51 Å. The P(3)-O(8) bond length is 1.58 Å. The P(3)-O(9) bond length is 1.51 Å. In the fourth P site, P(4) is bonded to one O(12), one O(13), one O(14), and one O(8) atom to form PO4 tetrahedra that share  a cornercorner with one U(1)O6 octahedra,  a cornercorner with one U(2)O6 octahedra,  a cornercorner with one U(3)O6 octahedra, and  a cornercorner with one P(3)O4 tetrahedra. The corner-sharing octahedral tilt angles range from 4-15°. The P(4)-O(12) bond length is 1.52 Å. The P(4)-O(13) bond length is 1.51 Å. The P(4)-O(14) bond length is 1.51 Å. The P(4)-O(8) bond length is 1.58 Å. In the fifth P site, P(5) is bonded to one O(15), one O(16), one O(17), and one O(18) atom to form PO4 tetrahedra that share  a cornercorner with one U(1)O6 octahedra,  a cornercorner with one U(2)O6 octahedra,  a cornercorner with one U(4)O6 octahedra, and  a cornercorner with one P(6)O4 tetrahedra. The corner-sharing octahedral tilt angles range from 9-19°. The P(5)-O(15) bond length is 1.58 Å. The P(5)-O(16) bond length is 1.51 Å. The P(5)-O(17) bond length is 1.51 Å. The P(5)-O(18) bond length is 1.51 Å. In the sixth P site, P(6) is bonded to one O(15), one O(19), one O(20), and one O(21) atom to form PO4 tetrahedra that share  a cornercorner with one U(1)O6 octahedra,  a cornercorner with one U(2)O6 octahedra,  a cornercorner with one U(4)O6 octahedra, and  a cornercorner with one P(5)O4 tetrahedra. The corner-sharing octahedral tilt angles range from 12-17°. The P(6)-O(15) bond length is 1.58 Å. The P(6)-O(19) bond length is 1.51 Å. The P(6)-O(20) bond length is 1.51 Å. The P(6)-O(21) bond length is 1.51 Å. In the seventh P site, P(7) is bonded to one O(22), one O(23), one O(24), and one O(25) atom to form PO4 tetrahedra that share  a cornercorner with one U(1)O6 octahedra,  a cornercorner with one U(3)O6 octahedra,  a cornercorner with one U(4)O6 octahedra, and  a cornercorner with one P(8)O4 tetrahedra. The corner-sharing octahedral tilt angles range from 11-15°. The P(7)-O(22) bond length is 1.58 Å. The P(7)-O(23) bond length is 1.51 Å. The P(7)-O(24) bond length is 1.52 Å. The P(7)-O(25) bond length is 1.51 Å. In the eighth P site, P(8) is bonded to one O(22), one O(26), one O(27), and one O(28) atom to form PO4 tetrahedra that share  a cornercorner with one U(1)O6 octahedra,  a cornercorner with one U(3)O6 octahedra,  a cornercorner with one U(4)O6 octahedra, and  a cornercorner with one P(7)O4 tetrahedra. The corner-sharing octahedral tilt angles range from 10-20°. The P(8)-O(22) bond length is 1.58 Å. The P(8)-O(26) bond length is 1.51 Å. The P(8)-O(27) bond length is 1.51 Å. The P(8)-O(28) bond length is 1.51 Å. There are twenty-eight inequivalent O sites. In the first O site, O(1) is bonded in a bent 150 degrees geometry to one P(1) and one P(2) atom. In the second O site, O(2) is bonded in a linear geometry to one U(4) and one P(1) atom. In the third O site, O(3) is bonded in a distorted bent 150 degrees geometry to one U(3) and one P(1) atom. In the fourth O site, O(4) is bonded in a linear geometry to one U(2) and one P(1) atom. In the fifth O site, O(5) is bonded in a distorted linear geometry to one U(4) and one P(2) atom. In the sixth O site, O(6) is bonded in a distorted bent 150 degrees geometry to one U(3) and one P(2) atom. In the seventh O site, O(7) is bonded in a linear geometry to one U(2) and one P(2) atom. In the eighth O site, O(8) is bonded in a bent 150 degrees geometry to one P(3) and one P(4) atom. In the ninth O site, O(9) is bonded in a distorted bent 150 degrees geometry to one U(1) and one P(3) atom. In the tenth O site, O(10) is bonded in a bent 150 degrees geometry to one U(2) and one P(3) atom. In the eleventh O site, O(11) is bonded in a bent 150 degrees geometry to one U(3) and one P(3) atom. In the twelfth O site, O(12) is bonded in a linear geometry to one U(1) and one P(4) atom. In the thirteenth O site, O(13) is bonded in a linear geometry to one U(2) and one P(4) atom. In the fourteenth O site, O(14) is bonded in a distorted linear geometry to one U(3) and one P(4) atom. In the fifteenth O site, O(15) is bonded in a bent 150 degrees geometry to one P(5) and one P(6) atom. In the sixteenth O site, O(16) is bonded in a distorted bent 150 degrees geometry to one U(2) and one P(5) atom. In the seventeenth O site, O(17) is bonded in a linear geometry to one U(1) and one P(5) atom. In the eighteenth O site, O(18) is bonded in a linear geometry to one U(4) and one P(5) atom. In the nineteenth O site, O(19) is bonded in a distorted linear geometry to one U(2) and one P(6) atom. In the twentieth O site, O(20) is bonded in a linear geometry to one U(1) and one P(6) atom. In the twenty-first O site, O(21) is bonded in a linear geometry to one U(4) and one P(6) atom. In the twenty-second O site, O(22) is bonded in a bent 150 degrees geometry to one P(7) and one P(8) atom. In the twenty-third O site, O(23) is bonded in a distorted linear geometry to one U(3) and one P(7) atom. In the twenty-fourth O site, O(24) is bonded in a linear geometry to one U(4) and one P(7) atom. In the twenty-fifth O site, O(25) is bonded in a linear geometry to one U(1) and one P(7) atom. In the twenty-sixth O site, O(26) is bonded in a distorted bent 150 degrees geometry to one U(3) and one P(8) atom. In the twenty-seventh O site, O(27) is bonded in a linear geometry to one U(4) and one P(8) atom. In the twenty-eighth O site, O(28) is bonded in a linear geometry to one U(1) and one P(8) atom.