RbSc(SO4)2 crystallizes in the trigonal P321 space group. Rb(1) is bonded to six equivalent O(1) and six equivalent O(2) atoms to form distorted RbO12 cuboctahedra that share edges with six equivalent Rb(1)O12 cuboctahedra, edges with six equivalent S(1)O4 tetrahedra, and faces with two equivalent Sc(1)O6 octahedra. Sc(1) is bonded to six equivalent O(1) atoms to form distorted ScO6 octahedra that share corners with six equivalent S(1)O4 tetrahedra and faces with two equivalent Rb(1)O12 cuboctahedra. S(1) is bonded to one O(2) and three equivalent O(1) atoms to form SO4 tetrahedra that share corners with three equivalent Sc(1)O6 octahedra and edges with three equivalent Rb(1)O12 cuboctahedra. The corner-sharing octahedral tilt angles are 34°. There are two inequivalent O sites. In the first O site, O(1) is bonded in a bent 150 degrees geometry to one Rb(1), one Sc(1), and one S(1) atom. In the second O site, O(2) is bonded in a single-bond geometry to three equivalent Rb(1) and one S(1) atom.
RbSc(SO4)2 crystallizes in the trigonal P321 space group. Rb(1) is bonded to six equivalent O(1) and six equivalent O(2) atoms to form distorted RbO12 cuboctahedra that share edges with six equivalent Rb(1)O12 cuboctahedra, edges with six equivalent S(1)O4 tetrahedra, and faces with two equivalent Sc(1)O6 octahedra. All Rb(1)-O(1) bond lengths are 3.47 Å. All Rb(1)-O(2) bond lengths are 3.11 Å. Sc(1) is bonded to six equivalent O(1) atoms to form distorted ScO6 octahedra that share corners with six equivalent S(1)O4 tetrahedra and faces with two equivalent Rb(1)O12 cuboctahedra. All Sc(1)-O(1) bond lengths are 2.11 Å. S(1) is bonded to one O(2) and three equivalent O(1) atoms to form SO4 tetrahedra that share corners with three equivalent Sc(1)O6 octahedra and edges with three equivalent Rb(1)O12 cuboctahedra. The corner-sharing octahedral tilt angles are 34°. The S(1)-O(2) bond length is 1.46 Å. All S(1)-O(1) bond lengths are 1.50 Å. There are two inequivalent O sites. In the first O site, O(1) is bonded in a bent 150 degrees geometry to one Rb(1), one Sc(1), and one S(1) atom. In the second O site, O(2) is bonded in a single-bond geometry to three equivalent Rb(1) and one S(1) atom.