U2Bi2O7 crystallizes in the orthorhombic Pmma space group. There are two inequivalent U sites. In the first U site, U(1) is bonded in a body-centered cubic geometry to two equivalent O(1), two equivalent O(2), two equivalent O(3), and two equivalent O(4) atoms. In the second U site, U(2) is bonded in a body-centered cubic geometry to two equivalent O(3), two equivalent O(5), and four equivalent O(4) atoms. There are two inequivalent Bi sites. In the first Bi site, Bi(1) is bonded in a distorted hexagonal planar geometry to two equivalent O(1) and four equivalent O(2) atoms. In the second Bi site, Bi(2) is bonded in a distorted hexagonal planar geometry to two equivalent O(2), two equivalent O(4), and two equivalent O(5) atoms. There are five inequivalent O sites. In the first O site, O(1) is bonded to two equivalent U(1) and two equivalent Bi(1) atoms to form OU2Bi2 tetrahedra that share corners with two equivalent O(3)U4 tetrahedra, corners with four equivalent O(1)U2Bi2 tetrahedra, corners with four equivalent O(4)U3Bi tetrahedra, corners with four equivalent O(2)UBi3 tetrahedra,  an edgeedge with one O(3)U4 tetrahedra, and edges with four equivalent O(2)UBi3 tetrahedra. In the second O site, O(2) is bonded to one U(1), one Bi(2), and two equivalent Bi(1) atoms to form OUBi3 tetrahedra that share corners with two equivalent O(1)U2Bi2 tetrahedra, corners with two equivalent O(5)U2Bi2 tetrahedra, corners with two equivalent O(4)U3Bi tetrahedra, corners with two equivalent O(3)U4 tetrahedra, corners with six equivalent O(2)UBi3 tetrahedra,  an edgeedge with one O(4)U3Bi tetrahedra,  an edgeedge with one O(2)UBi3 tetrahedra, and edges with two equivalent O(1)U2Bi2 tetrahedra. In the third O site, O(3) is bonded to two equivalent U(1) and two equivalent U(2) atoms to form OU4 tetrahedra that share corners with two equivalent O(1)U2Bi2 tetrahedra, corners with two equivalent O(5)U2Bi2 tetrahedra, corners with four equivalent O(4)U3Bi tetrahedra, corners with four equivalent O(3)U4 tetrahedra, corners with four equivalent O(2)UBi3 tetrahedra,  an edgeedge with one O(1)U2Bi2 tetrahedra,  an edgeedge with one O(5)U2Bi2 tetrahedra, and edges with four equivalent O(4)U3Bi tetrahedra. In the fourth O site, O(4) is bonded to one U(1), two equivalent U(2), and one Bi(2) atom to form OU3Bi tetrahedra that share corners with two equivalent O(1)U2Bi2 tetrahedra, corners with two equivalent O(5)U2Bi2 tetrahedra, corners with two equivalent O(3)U4 tetrahedra, corners with two equivalent O(2)UBi3 tetrahedra, corners with six equivalent O(4)U3Bi tetrahedra,  an edgeedge with one O(4)U3Bi tetrahedra,  an edgeedge with one O(2)UBi3 tetrahedra, edges with two equivalent O(5)U2Bi2 tetrahedra, and edges with two equivalent O(3)U4 tetrahedra. In the fifth O site, O(5) is bonded to two equivalent U(2) and two equivalent Bi(2) atoms to form OU2Bi2 tetrahedra that share corners with two equivalent O(3)U4 tetrahedra, corners with four equivalent O(5)U2Bi2 tetrahedra, corners with four equivalent O(4)U3Bi tetrahedra, corners with four equivalent O(2)UBi3 tetrahedra,  an edgeedge with one O(3)U4 tetrahedra, and edges with four equivalent O(4)U3Bi tetrahedra.
U2Bi2O7 crystallizes in the orthorhombic Pmma space group. There are two inequivalent U sites. In the first U site, U(1) is bonded in a body-centered cubic geometry to two equivalent O(1), two equivalent O(2), two equivalent O(3), and two equivalent O(4) atoms. Both U(1)-O(1) bond lengths are 2.23 Å. Both U(1)-O(2) bond lengths are 2.27 Å. Both U(1)-O(3) bond lengths are 2.36 Å. Both U(1)-O(4) bond lengths are 2.28 Å. In the second U site, U(2) is bonded in a body-centered cubic geometry to two equivalent O(3), two equivalent O(5), and four equivalent O(4) atoms. Both U(2)-O(3) bond lengths are 2.34 Å. Both U(2)-O(5) bond lengths are 2.24 Å. All U(2)-O(4) bond lengths are 2.33 Å. There are two inequivalent Bi sites. In the first Bi site, Bi(1) is bonded in a distorted hexagonal planar geometry to two equivalent O(1) and four equivalent O(2) atoms. Both Bi(1)-O(1) bond lengths are 2.56 Å. All Bi(1)-O(2) bond lengths are 2.43 Å. In the second Bi site, Bi(2) is bonded in a distorted hexagonal planar geometry to two equivalent O(2), two equivalent O(4), and two equivalent O(5) atoms. Both Bi(2)-O(2) bond lengths are 2.32 Å. Both Bi(2)-O(4) bond lengths are 2.59 Å. Both Bi(2)-O(5) bond lengths are 2.59 Å. There are five inequivalent O sites. In the first O site, O(1) is bonded to two equivalent U(1) and two equivalent Bi(1) atoms to form OU2Bi2 tetrahedra that share corners with two equivalent O(3)U4 tetrahedra, corners with four equivalent O(1)U2Bi2 tetrahedra, corners with four equivalent O(4)U3Bi tetrahedra, corners with four equivalent O(2)UBi3 tetrahedra,  an edgeedge with one O(3)U4 tetrahedra, and edges with four equivalent O(2)UBi3 tetrahedra. In the second O site, O(2) is bonded to one U(1), one Bi(2), and two equivalent Bi(1) atoms to form OUBi3 tetrahedra that share corners with two equivalent O(1)U2Bi2 tetrahedra, corners with two equivalent O(5)U2Bi2 tetrahedra, corners with two equivalent O(4)U3Bi tetrahedra, corners with two equivalent O(3)U4 tetrahedra, corners with six equivalent O(2)UBi3 tetrahedra,  an edgeedge with one O(4)U3Bi tetrahedra,  an edgeedge with one O(2)UBi3 tetrahedra, and edges with two equivalent O(1)U2Bi2 tetrahedra. In the third O site, O(3) is bonded to two equivalent U(1) and two equivalent U(2) atoms to form OU4 tetrahedra that share corners with two equivalent O(1)U2Bi2 tetrahedra, corners with two equivalent O(5)U2Bi2 tetrahedra, corners with four equivalent O(4)U3Bi tetrahedra, corners with four equivalent O(3)U4 tetrahedra, corners with four equivalent O(2)UBi3 tetrahedra,  an edgeedge with one O(1)U2Bi2 tetrahedra,  an edgeedge with one O(5)U2Bi2 tetrahedra, and edges with four equivalent O(4)U3Bi tetrahedra. In the fourth O site, O(4) is bonded to one U(1), two equivalent U(2), and one Bi(2) atom to form OU3Bi tetrahedra that share corners with two equivalent O(1)U2Bi2 tetrahedra, corners with two equivalent O(5)U2Bi2 tetrahedra, corners with two equivalent O(3)U4 tetrahedra, corners with two equivalent O(2)UBi3 tetrahedra, corners with six equivalent O(4)U3Bi tetrahedra,  an edgeedge with one O(4)U3Bi tetrahedra,  an edgeedge with one O(2)UBi3 tetrahedra, edges with two equivalent O(5)U2Bi2 tetrahedra, and edges with two equivalent O(3)U4 tetrahedra. In the fifth O site, O(5) is bonded to two equivalent U(2) and two equivalent Bi(2) atoms to form OU2Bi2 tetrahedra that share corners with two equivalent O(3)U4 tetrahedra, corners with four equivalent O(5)U2Bi2 tetrahedra, corners with four equivalent O(4)U3Bi tetrahedra, corners with four equivalent O(2)UBi3 tetrahedra,  an edgeedge with one O(3)U4 tetrahedra, and edges with four equivalent O(4)U3Bi tetrahedra.