RbGdSe2 is Caswellsilverite structured and crystallizes in the trigonal R-3m space group. Rb(1) is bonded to six equivalent Se(1) atoms to form distorted RbSe6 octahedra that share corners with six equivalent Gd(1)Se6 octahedra, edges with six equivalent Rb(1)Se6 octahedra, and edges with six equivalent Gd(1)Se6 octahedra. The corner-sharing octahedral tilt angles are 12°. Gd(1) is bonded to six equivalent Se(1) atoms to form GdSe6 octahedra that share corners with six equivalent Rb(1)Se6 octahedra, edges with six equivalent Rb(1)Se6 octahedra, and edges with six equivalent Gd(1)Se6 octahedra. The corner-sharing octahedral tilt angles are 12°. Se(1) is bonded to three equivalent Rb(1) and three equivalent Gd(1) atoms to form a mixture of corner and edge-sharing SeRb3Gd3 octahedra. The corner-sharing octahedra are not tilted.
RbGdSe2 is Caswellsilverite structured and crystallizes in the trigonal R-3m space group. Rb(1) is bonded to six equivalent Se(1) atoms to form distorted RbSe6 octahedra that share corners with six equivalent Gd(1)Se6 octahedra, edges with six equivalent Rb(1)Se6 octahedra, and edges with six equivalent Gd(1)Se6 octahedra. The corner-sharing octahedral tilt angles are 12°. All Rb(1)-Se(1) bond lengths are 3.44 Å. Gd(1) is bonded to six equivalent Se(1) atoms to form GdSe6 octahedra that share corners with six equivalent Rb(1)Se6 octahedra, edges with six equivalent Rb(1)Se6 octahedra, and edges with six equivalent Gd(1)Se6 octahedra. The corner-sharing octahedral tilt angles are 12°. All Gd(1)-Se(1) bond lengths are 2.92 Å. Se(1) is bonded to three equivalent Rb(1) and three equivalent Gd(1) atoms to form a mixture of corner and edge-sharing SeRb3Gd3 octahedra. The corner-sharing octahedra are not tilted.