Rb2Nb2O5 crystallizes in the orthorhombic Ima2 space group. Rb(1) is bonded in a 10-coordinate geometry to two equivalent O(3), four equivalent O(1), and four equivalent O(2) atoms. There are two inequivalent Nb sites. In the first Nb site, Nb(1) is bonded to two equivalent O(2) and four equivalent O(1) atoms to form corner-sharing NbO6 octahedra. The corner-sharing octahedral tilt angles are 6°. In the second Nb site, Nb(2) is bonded in a distorted see-saw-like geometry to two equivalent O(2) and two equivalent O(3) atoms. There are three inequivalent O sites. In the first O site, O(1) is bonded to four equivalent Rb(1) and two equivalent Nb(1) atoms to form a mixture of distorted edge, corner, and face-sharing ORb4Nb2 octahedra. The corner-sharing octahedral tilt angles are 6°. In the second O site, O(2) is bonded in a 2-coordinate geometry to four equivalent Rb(1), one Nb(1), and one Nb(2) atom. In the third O site, O(3) is bonded in a distorted linear geometry to four equivalent Rb(1) and two equivalent Nb(2) atoms.
Rb2Nb2O5 crystallizes in the orthorhombic Ima2 space group. Rb(1) is bonded in a 10-coordinate geometry to two equivalent O(3), four equivalent O(1), and four equivalent O(2) atoms. There is one shorter (2.98 Å) and one longer (3.02 Å) Rb(1)-O(3) bond length. There are a spread of Rb(1)-O(1) bond distances ranging from 2.87-2.92 Å. There are a spread of Rb(1)-O(2) bond distances ranging from 2.89-3.12 Å. There are two inequivalent Nb sites. In the first Nb site, Nb(1) is bonded to two equivalent O(2) and four equivalent O(1) atoms to form corner-sharing NbO6 octahedra. The corner-sharing octahedral tilt angles are 6°. Both Nb(1)-O(2) bond lengths are 2.09 Å. There are two shorter (1.94 Å) and two longer (2.32 Å) Nb(1)-O(1) bond lengths. In the second Nb site, Nb(2) is bonded in a distorted see-saw-like geometry to two equivalent O(2) and two equivalent O(3) atoms. Both Nb(2)-O(2) bond lengths are 1.99 Å. Both Nb(2)-O(3) bond lengths are 1.96 Å. There are three inequivalent O sites. In the first O site, O(1) is bonded to four equivalent Rb(1) and two equivalent Nb(1) atoms to form a mixture of distorted edge, corner, and face-sharing ORb4Nb2 octahedra. The corner-sharing octahedral tilt angles are 6°. In the second O site, O(2) is bonded in a 2-coordinate geometry to four equivalent Rb(1), one Nb(1), and one Nb(2) atom. In the third O site, O(3) is bonded in a distorted linear geometry to four equivalent Rb(1) and two equivalent Nb(2) atoms.