Rb4Nb11O30 crystallizes in the trigonal R-3m space group. There are two inequivalent Rb sites. In the first Rb site, Rb(1) is bonded in a 6-coordinate geometry to three equivalent O(3) and three equivalent O(4) atoms. In the second Rb site, Rb(2) is bonded to three equivalent O(1) and three equivalent O(5) atoms to form distorted RbO6 octahedra that share corners with three equivalent Nb(1)O6 octahedra, corners with three equivalent Nb(2)O6 octahedra, and corners with six equivalent Nb(3)O6 octahedra. The corner-sharing octahedral tilt angles range from 69-78°. There are three inequivalent Nb sites. In the first Nb site, Nb(1) is bonded to one O(1), two equivalent O(4), and three equivalent O(3) atoms to form distorted NbO6 octahedra that share  a cornercorner with one Rb(2)O6 octahedra,  a cornercorner with one Nb(2)O6 octahedra, corners with four equivalent Nb(1)O6 octahedra, and edges with two equivalent Nb(1)O6 octahedra. The corner-sharing octahedral tilt angles range from 26-69°. In the second Nb site, Nb(2) is bonded to three equivalent O(1) and three equivalent O(2) atoms to form NbO6 octahedra that share corners with three equivalent Rb(2)O6 octahedra, corners with three equivalent Nb(1)O6 octahedra, and corners with three equivalent Nb(3)O6 octahedra. The corner-sharing octahedral tilt angles range from 33-78°. In the third Nb site, Nb(3) is bonded to two equivalent O(2) and four equivalent O(5) atoms to form NbO6 octahedra that share corners with two equivalent Nb(2)O6 octahedra, corners with four equivalent Rb(2)O6 octahedra, and corners with four equivalent Nb(3)O6 octahedra. The corner-sharing octahedral tilt angles range from 37-71°. There are five inequivalent O sites. In the first O site, O(5) is bonded in a distorted bent 150 degrees geometry to one Rb(2) and two equivalent Nb(3) atoms. In the second O site, O(1) is bonded in a bent 150 degrees geometry to one Rb(2), one Nb(1), and one Nb(2) atom. In the third O site, O(2) is bonded in a bent 150 degrees geometry to one Nb(2) and one Nb(3) atom. In the fourth O site, O(3) is bonded in a distorted trigonal non-coplanar geometry to one Rb(1) and three equivalent Nb(1) atoms. In the fifth O site, O(4) is bonded in a bent 150 degrees geometry to one Rb(1) and two equivalent Nb(1) atoms.
Rb4Nb11O30 crystallizes in the trigonal R-3m space group. There are two inequivalent Rb sites. In the first Rb site, Rb(1) is bonded in a 6-coordinate geometry to three equivalent O(3) and three equivalent O(4) atoms. All Rb(1)-O(3) bond lengths are 3.26 Å. All Rb(1)-O(4) bond lengths are 3.25 Å. In the second Rb site, Rb(2) is bonded to three equivalent O(1) and three equivalent O(5) atoms to form distorted RbO6 octahedra that share corners with three equivalent Nb(1)O6 octahedra, corners with three equivalent Nb(2)O6 octahedra, and corners with six equivalent Nb(3)O6 octahedra. The corner-sharing octahedral tilt angles range from 69-78°. All Rb(2)-O(1) bond lengths are 3.53 Å. All Rb(2)-O(5) bond lengths are 3.28 Å. There are three inequivalent Nb sites. In the first Nb site, Nb(1) is bonded to one O(1), two equivalent O(4), and three equivalent O(3) atoms to form distorted NbO6 octahedra that share  a cornercorner with one Rb(2)O6 octahedra,  a cornercorner with one Nb(2)O6 octahedra, corners with four equivalent Nb(1)O6 octahedra, and edges with two equivalent Nb(1)O6 octahedra. The corner-sharing octahedral tilt angles range from 26-69°. The Nb(1)-O(1) bond length is 1.86 Å. Both Nb(1)-O(4) bond lengths are 1.95 Å. There are two shorter (2.10 Å) and one longer (2.17 Å) Nb(1)-O(3) bond length. In the second Nb site, Nb(2) is bonded to three equivalent O(1) and three equivalent O(2) atoms to form NbO6 octahedra that share corners with three equivalent Rb(2)O6 octahedra, corners with three equivalent Nb(1)O6 octahedra, and corners with three equivalent Nb(3)O6 octahedra. The corner-sharing octahedral tilt angles range from 33-78°. All Nb(2)-O(1) bond lengths are 2.12 Å. All Nb(2)-O(2) bond lengths are 1.92 Å. In the third Nb site, Nb(3) is bonded to two equivalent O(2) and four equivalent O(5) atoms to form NbO6 octahedra that share corners with two equivalent Nb(2)O6 octahedra, corners with four equivalent Rb(2)O6 octahedra, and corners with four equivalent Nb(3)O6 octahedra. The corner-sharing octahedral tilt angles range from 37-71°. Both Nb(3)-O(2) bond lengths are 2.02 Å. All Nb(3)-O(5) bond lengths are 2.01 Å. There are five inequivalent O sites. In the first O site, O(5) is bonded in a distorted bent 150 degrees geometry to one Rb(2) and two equivalent Nb(3) atoms. In the second O site, O(1) is bonded in a bent 150 degrees geometry to one Rb(2), one Nb(1), and one Nb(2) atom. In the third O site, O(2) is bonded in a bent 150 degrees geometry to one Nb(2) and one Nb(3) atom. In the fourth O site, O(3) is bonded in a distorted trigonal non-coplanar geometry to one Rb(1) and three equivalent Nb(1) atoms. In the fifth O site, O(4) is bonded in a bent 150 degrees geometry to one Rb(1) and two equivalent Nb(1) atoms.