RbGa(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 Ga(1)O6 pentagonal pyramids. Ga(1) is bonded to six equivalent O(1) atoms to form distorted GaO6 pentagonal pyramids 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 Ga(1)O6 pentagonal pyramids and edges with three equivalent Rb(1)O12 cuboctahedra. 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 Ga(1), and one S(1) atom. In the second O site, O(2) is bonded in a distorted single-bond geometry to three equivalent Rb(1) and one S(1) atom.
RbGa(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 Ga(1)O6 pentagonal pyramids. All Rb(1)-O(1) bond lengths are 3.41 Å. All Rb(1)-O(2) bond lengths are 3.02 Å. Ga(1) is bonded to six equivalent O(1) atoms to form distorted GaO6 pentagonal pyramids that share corners with six equivalent S(1)O4 tetrahedra and faces with two equivalent Rb(1)O12 cuboctahedra. All Ga(1)-O(1) bond lengths are 2.00 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 Ga(1)O6 pentagonal pyramids and edges with three equivalent Rb(1)O12 cuboctahedra. 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 Ga(1), and one S(1) atom. In the second O site, O(2) is bonded in a distorted single-bond geometry to three equivalent Rb(1) and one S(1) atom.