Rb2Mo2O7 crystallizes in the orthorhombic Ama2 space group. There are four inequivalent Rb sites. In the first Rb site, Rb(1) is bonded in a 7-coordinate geometry to one O(5), two equivalent O(2), two equivalent O(3), and two equivalent O(4) atoms. In the second Rb site, Rb(2) is bonded in a 8-coordinate geometry to one O(5), one O(8), two equivalent O(3), two equivalent O(6), and two equivalent O(7) atoms. In the third Rb site, Rb(3) is bonded in a 8-coordinate geometry to two equivalent O(1), two equivalent O(2), two equivalent O(7), and two equivalent O(8) atoms. In the fourth Rb site, Rb(4) is bonded to one O(8), two equivalent O(3), two equivalent O(4), and two equivalent O(7) atoms to form distorted RbO7 hexagonal pyramids that share corners with two equivalent Mo(3)O6 octahedra,  a cornercorner with one Mo(2)O4 tetrahedra, and corners with four equivalent Mo(1)O4 tetrahedra. The corner-sharing octahedral tilt angles are 22°. There are three inequivalent Mo sites. In the first Mo site, Mo(1) is bonded to one O(2), one O(3), one O(6), and one O(7) atom to form MoO4 tetrahedra that share corners with two equivalent Rb(4)O7 hexagonal pyramids and  a cornercorner with one Mo(3)O6 octahedra. The corner-sharing octahedral tilt angles are 35°. In the second Mo site, Mo(2) is bonded to one O(5), one O(8), and two equivalent O(1) atoms to form MoO4 tetrahedra that share  a cornercorner with one Rb(4)O7 hexagonal pyramid and corners with two equivalent Mo(3)O6 octahedra. The corner-sharing octahedral tilt angles are 43°. In the third Mo site, Mo(3) is bonded to two equivalent O(1), two equivalent O(4), and two equivalent O(6) atoms to form distorted MoO6 octahedra that share corners with two equivalent Rb(4)O7 hexagonal pyramids, corners with two equivalent Mo(1)O4 tetrahedra, and corners with two equivalent Mo(2)O4 tetrahedra. There are eight inequivalent O sites. In the first O site, O(1) is bonded in a 3-coordinate geometry to one Rb(3), one Mo(2), and one Mo(3) atom. In the second O site, O(2) is bonded in a distorted single-bond geometry to one Rb(1), one Rb(3), and one Mo(1) atom. In the third O site, O(3) is bonded in a distorted single-bond geometry to one Rb(1), one Rb(2), one Rb(4), and one Mo(1) atom. In the fourth O site, O(4) is bonded in a distorted single-bond geometry to one Rb(1), one Rb(4), and one Mo(3) atom. In the fifth O site, O(5) is bonded in a distorted single-bond geometry to one Rb(1), one Rb(2), and one Mo(2) atom. In the sixth O site, O(6) is bonded in a distorted bent 150 degrees geometry to one Rb(2), one Mo(1), and one Mo(3) atom. In the seventh O site, O(7) is bonded in a distorted single-bond geometry to one Rb(2), one Rb(3), one Rb(4), and one Mo(1) atom. In the eighth O site, O(8) is bonded in a distorted single-bond geometry to one Rb(2), one Rb(4), two equivalent Rb(3), and one Mo(2) atom.
Rb2Mo2O7 crystallizes in the orthorhombic Ama2 space group. There are four inequivalent Rb sites. In the first Rb site, Rb(1) is bonded in a 7-coordinate geometry to one O(5), two equivalent O(2), two equivalent O(3), and two equivalent O(4) atoms. The Rb(1)-O(5) bond length is 3.10 Å. Both Rb(1)-O(2) bond lengths are 3.05 Å. Both Rb(1)-O(3) bond lengths are 3.03 Å. Both Rb(1)-O(4) bond lengths are 3.10 Å. In the second Rb site, Rb(2) is bonded in a 8-coordinate geometry to one O(5), one O(8), two equivalent O(3), two equivalent O(6), and two equivalent O(7) atoms. The Rb(2)-O(5) bond length is 3.00 Å. The Rb(2)-O(8) bond length is 3.57 Å. Both Rb(2)-O(3) bond lengths are 3.17 Å. Both Rb(2)-O(6) bond lengths are 3.27 Å. Both Rb(2)-O(7) bond lengths are 3.13 Å. In the third Rb site, Rb(3) is bonded in a 8-coordinate geometry to two equivalent O(1), two equivalent O(2), two equivalent O(7), and two equivalent O(8) atoms. Both Rb(3)-O(1) bond lengths are 3.22 Å. Both Rb(3)-O(2) bond lengths are 2.96 Å. Both Rb(3)-O(7) bond lengths are 3.08 Å. Both Rb(3)-O(8) bond lengths are 3.08 Å. In the fourth Rb site, Rb(4) is bonded to one O(8), two equivalent O(3), two equivalent O(4), and two equivalent O(7) atoms to form distorted RbO7 hexagonal pyramids that share corners with two equivalent Mo(3)O6 octahedra,  a cornercorner with one Mo(2)O4 tetrahedra, and corners with four equivalent Mo(1)O4 tetrahedra. The corner-sharing octahedral tilt angles are 22°. The Rb(4)-O(8) bond length is 2.95 Å. Both Rb(4)-O(3) bond lengths are 2.95 Å. Both Rb(4)-O(4) bond lengths are 2.92 Å. Both Rb(4)-O(7) bond lengths are 2.90 Å. There are three inequivalent Mo sites. In the first Mo site, Mo(1) is bonded to one O(2), one O(3), one O(6), and one O(7) atom to form MoO4 tetrahedra that share corners with two equivalent Rb(4)O7 hexagonal pyramids and  a cornercorner with one Mo(3)O6 octahedra. The corner-sharing octahedral tilt angles are 35°. The Mo(1)-O(2) bond length is 1.77 Å. The Mo(1)-O(3) bond length is 1.77 Å. The Mo(1)-O(6) bond length is 1.90 Å. The Mo(1)-O(7) bond length is 1.78 Å. In the second Mo site, Mo(2) is bonded to one O(5), one O(8), and two equivalent O(1) atoms to form MoO4 tetrahedra that share  a cornercorner with one Rb(4)O7 hexagonal pyramid and corners with two equivalent Mo(3)O6 octahedra. The corner-sharing octahedral tilt angles are 43°. The Mo(2)-O(5) bond length is 1.77 Å. The Mo(2)-O(8) bond length is 1.79 Å. Both Mo(2)-O(1) bond lengths are 1.83 Å. In the third Mo site, Mo(3) is bonded to two equivalent O(1), two equivalent O(4), and two equivalent O(6) atoms to form distorted MoO6 octahedra that share corners with two equivalent Rb(4)O7 hexagonal pyramids, corners with two equivalent Mo(1)O4 tetrahedra, and corners with two equivalent Mo(2)O4 tetrahedra. Both Mo(3)-O(1) bond lengths are 2.32 Å. Both Mo(3)-O(4) bond lengths are 1.75 Å. Both Mo(3)-O(6) bond lengths are 1.96 Å. There are eight inequivalent O sites. In the first O site, O(1) is bonded in a 3-coordinate geometry to one Rb(3), one Mo(2), and one Mo(3) atom. In the second O site, O(2) is bonded in a distorted single-bond geometry to one Rb(1), one Rb(3), and one Mo(1) atom. In the third O site, O(3) is bonded in a distorted single-bond geometry to one Rb(1), one Rb(2), one Rb(4), and one Mo(1) atom. In the fourth O site, O(4) is bonded in a distorted single-bond geometry to one Rb(1), one Rb(4), and one Mo(3) atom. In the fifth O site, O(5) is bonded in a distorted single-bond geometry to one Rb(1), one Rb(2), and one Mo(2) atom. In the sixth O site, O(6) is bonded in a distorted bent 150 degrees geometry to one Rb(2), one Mo(1), and one Mo(3) atom. In the seventh O site, O(7) is bonded in a distorted single-bond geometry to one Rb(2), one Rb(3), one Rb(4), and one Mo(1) atom. In the eighth O site, O(8) is bonded in a distorted single-bond geometry to one Rb(2), one Rb(4), two equivalent Rb(3), and one Mo(2) atom.