Rb2Yb2O5 crystallizes in the tetragonal P4/mmm space group. There are two inequivalent Rb sites. In the first Rb site, Rb(1) is bonded in a body-centered cubic geometry to eight equivalent O(1) atoms. In the second Rb site, Rb(2) is bonded to four equivalent O(2) and eight equivalent O(1) atoms to form RbO12 cuboctahedra that share corners with four equivalent Rb(2)O12 cuboctahedra, faces with four equivalent Rb(2)O12 cuboctahedra, and faces with eight equivalent Yb(1)O5 square pyramids. Yb(1) is bonded to one O(2) and four equivalent O(1) atoms to form distorted YbO5 square pyramids that share corners with five equivalent Yb(1)O5 square pyramids and faces with four equivalent Rb(2)O12 cuboctahedra. There are two inequivalent O sites. In the first O site, O(1) is bonded in a 2-coordinate geometry to two equivalent Rb(1), two equivalent Rb(2), and two equivalent Yb(1) atoms. In the second O site, O(2) is bonded to four equivalent Rb(2) and two equivalent Yb(1) atoms to form a mixture of distorted corner and edge-sharing ORb4Yb2 octahedra. The corner-sharing octahedra are not tilted.
Rb2Yb2O5 crystallizes in the tetragonal P4/mmm space group. There are two inequivalent Rb sites. In the first Rb site, Rb(1) is bonded in a body-centered cubic geometry to eight equivalent O(1) atoms. All Rb(1)-O(1) bond lengths are 3.00 Å. In the second Rb site, Rb(2) is bonded to four equivalent O(2) and eight equivalent O(1) atoms to form RbO12 cuboctahedra that share corners with four equivalent Rb(2)O12 cuboctahedra, faces with four equivalent Rb(2)O12 cuboctahedra, and faces with eight equivalent Yb(1)O5 square pyramids. All Rb(2)-O(2) bond lengths are 3.12 Å. All Rb(2)-O(1) bond lengths are 3.45 Å. Yb(1) is bonded to one O(2) and four equivalent O(1) atoms to form distorted YbO5 square pyramids that share corners with five equivalent Yb(1)O5 square pyramids and faces with four equivalent Rb(2)O12 cuboctahedra. The Yb(1)-O(2) bond length is 2.20 Å. All Yb(1)-O(1) bond lengths are 2.26 Å. There are two inequivalent O sites. In the first O site, O(1) is bonded in a 2-coordinate geometry to two equivalent Rb(1), two equivalent Rb(2), and two equivalent Yb(1) atoms. In the second O site, O(2) is bonded to four equivalent Rb(2) and two equivalent Yb(1) atoms to form a mixture of distorted corner and edge-sharing ORb4Yb2 octahedra. The corner-sharing octahedra are not tilted.