Rb2U2O7 crystallizes in the triclinic P-1 space group. There are two inequivalent Rb sites. In the first Rb site, Rb(1) is bonded to one O(3), one O(5), two equivalent O(1), and two equivalent O(7) atoms to form distorted RbO6 octahedra that share  a cornercorner with one U(2)O6 octahedra, corners with two equivalent U(3)O6 octahedra, edges with two equivalent Rb(1)O6 octahedra, and edges with four equivalent Rb(2)O6 octahedra. The corner-sharing octahedral tilt angles range from 47-59°. In the second Rb site, Rb(2) is bonded to one O(1), one O(7), two equivalent O(3), and two equivalent O(5) atoms to form distorted RbO6 octahedra that share  a cornercorner with one U(3)O6 octahedra, corners with two equivalent U(2)O6 octahedra, edges with two equivalent Rb(2)O6 octahedra, and edges with four equivalent Rb(1)O6 octahedra. The corner-sharing octahedral tilt angles range from 55-59°. There are three inequivalent U sites. In the first U site, U(1) is bonded in a 7-coordinate geometry to one O(1), one O(3), one O(6), two equivalent O(2), and two equivalent O(4) atoms. In the second U site, U(2) is bonded to two equivalent O(4), two equivalent O(5), and two equivalent O(6) atoms to form UO6 octahedra that share corners with two equivalent Rb(1)O6 octahedra, corners with two equivalent U(3)O6 octahedra, and corners with four equivalent Rb(2)O6 octahedra. The corner-sharing octahedral tilt angles range from 47-59°. In the third U site, U(3) is bonded to two equivalent O(2), two equivalent O(6), and two equivalent O(7) atoms to form UO6 octahedra that share corners with two equivalent Rb(2)O6 octahedra, corners with two equivalent U(2)O6 octahedra, and corners with four equivalent Rb(1)O6 octahedra. The corner-sharing octahedral tilt angles range from 48-59°. There are seven inequivalent O sites. In the first O site, O(1) is bonded in a distorted rectangular see-saw-like geometry to one Rb(2), two equivalent Rb(1), and one U(1) atom. In the second O site, O(2) is bonded in a 2-coordinate geometry to one U(3) and two equivalent U(1) atoms. In the third O site, O(3) is bonded in a distorted rectangular see-saw-like geometry to one Rb(1), two equivalent Rb(2), and one U(1) atom. In the fourth O site, O(4) is bonded in a 3-coordinate geometry to one U(2) and two equivalent U(1) atoms. In the fifth O site, O(5) is bonded in a distorted rectangular see-saw-like geometry to one Rb(1), two equivalent Rb(2), and one U(2) atom. In the sixth O site, O(6) is bonded in a trigonal planar geometry to one U(1), one U(2), and one U(3) atom. In the seventh O site, O(7) is bonded in a distorted rectangular see-saw-like geometry to one Rb(2), two equivalent Rb(1), and one U(3) atom.
Rb2U2O7 crystallizes in the triclinic P-1 space group. There are two inequivalent Rb sites. In the first Rb site, Rb(1) is bonded to one O(3), one O(5), two equivalent O(1), and two equivalent O(7) atoms to form distorted RbO6 octahedra that share  a cornercorner with one U(2)O6 octahedra, corners with two equivalent U(3)O6 octahedra, edges with two equivalent Rb(1)O6 octahedra, and edges with four equivalent Rb(2)O6 octahedra. The corner-sharing octahedral tilt angles range from 47-59°. The Rb(1)-O(3) bond length is 2.86 Å. The Rb(1)-O(5) bond length is 2.79 Å. There is one shorter (2.78 Å) and one longer (3.02 Å) Rb(1)-O(1) bond length. There is one shorter (2.84 Å) and one longer (2.89 Å) Rb(1)-O(7) bond length. In the second Rb site, Rb(2) is bonded to one O(1), one O(7), two equivalent O(3), and two equivalent O(5) atoms to form distorted RbO6 octahedra that share  a cornercorner with one U(3)O6 octahedra, corners with two equivalent U(2)O6 octahedra, edges with two equivalent Rb(2)O6 octahedra, and edges with four equivalent Rb(1)O6 octahedra. The corner-sharing octahedral tilt angles range from 55-59°. The Rb(2)-O(1) bond length is 2.81 Å. The Rb(2)-O(7) bond length is 2.91 Å. There is one shorter (2.75 Å) and one longer (2.91 Å) Rb(2)-O(3) bond length. There is one shorter (2.79 Å) and one longer (2.86 Å) Rb(2)-O(5) bond length. There are three inequivalent U sites. In the first U site, U(1) is bonded in a 7-coordinate geometry to one O(1), one O(3), one O(6), two equivalent O(2), and two equivalent O(4) atoms. The U(1)-O(1) bond length is 1.85 Å. The U(1)-O(3) bond length is 1.86 Å. The U(1)-O(6) bond length is 2.34 Å. There is one shorter (2.20 Å) and one longer (2.68 Å) U(1)-O(2) bond length. There is one shorter (2.22 Å) and one longer (2.57 Å) U(1)-O(4) bond length. In the second U site, U(2) is bonded to two equivalent O(4), two equivalent O(5), and two equivalent O(6) atoms to form UO6 octahedra that share corners with two equivalent Rb(1)O6 octahedra, corners with two equivalent U(3)O6 octahedra, and corners with four equivalent Rb(2)O6 octahedra. The corner-sharing octahedral tilt angles range from 47-59°. Both U(2)-O(4) bond lengths are 2.21 Å. Both U(2)-O(5) bond lengths are 1.88 Å. Both U(2)-O(6) bond lengths are 2.19 Å. In the third U site, U(3) is bonded to two equivalent O(2), two equivalent O(6), and two equivalent O(7) atoms to form UO6 octahedra that share corners with two equivalent Rb(2)O6 octahedra, corners with two equivalent U(2)O6 octahedra, and corners with four equivalent Rb(1)O6 octahedra. The corner-sharing octahedral tilt angles range from 48-59°. Both U(3)-O(2) bond lengths are 2.21 Å. Both U(3)-O(6) bond lengths are 2.20 Å. Both U(3)-O(7) bond lengths are 1.88 Å. There are seven inequivalent O sites. In the first O site, O(1) is bonded in a distorted rectangular see-saw-like geometry to one Rb(2), two equivalent Rb(1), and one U(1) atom. In the second O site, O(2) is bonded in a 2-coordinate geometry to one U(3) and two equivalent U(1) atoms. In the third O site, O(3) is bonded in a distorted rectangular see-saw-like geometry to one Rb(1), two equivalent Rb(2), and one U(1) atom. In the fourth O site, O(4) is bonded in a 3-coordinate geometry to one U(2) and two equivalent U(1) atoms. In the fifth O site, O(5) is bonded in a distorted rectangular see-saw-like geometry to one Rb(1), two equivalent Rb(2), and one U(2) atom. In the sixth O site, O(6) is bonded in a trigonal planar geometry to one U(1), one U(2), and one U(3) atom. In the seventh O site, O(7) is bonded in a distorted rectangular see-saw-like geometry to one Rb(2), two equivalent Rb(1), and one U(3) atom.