RbSeBr3 is (Cubic) Perovskite structured and crystallizes in the tetragonal P4mm space group. Rb(1) is bonded to four equivalent Br(2) and eight equivalent Br(1) atoms to form RbBr12 cuboctahedra that share corners with twelve equivalent Rb(1)Br12 cuboctahedra, faces with six equivalent Rb(1)Br12 cuboctahedra, and faces with eight equivalent Se(1)Br6 octahedra. Se(1) is bonded to two equivalent Br(2) and four equivalent Br(1) atoms to form SeBr6 octahedra that share corners with six equivalent Se(1)Br6 octahedra and faces with eight equivalent Rb(1)Br12 cuboctahedra. The corner-sharing octahedra are not tilted. There are two inequivalent Br sites. In the first Br site, Br(1) is bonded to four equivalent Rb(1) and two equivalent Se(1) atoms to form a mixture of corner, face, and edge-sharing BrRb4Se2 octahedra. The corner-sharing octahedral tilt angles range from 0-61°. In the second Br site, Br(2) is bonded to four equivalent Rb(1) and two equivalent Se(1) atoms to form a mixture of corner, face, and edge-sharing BrRb4Se2 octahedra. The corner-sharing octahedral tilt angles range from 0-61°.
RbSeBr3 is (Cubic) Perovskite structured and crystallizes in the tetragonal P4mm space group. Rb(1) is bonded to four equivalent Br(2) and eight equivalent Br(1) atoms to form RbBr12 cuboctahedra that share corners with twelve equivalent Rb(1)Br12 cuboctahedra, faces with six equivalent Rb(1)Br12 cuboctahedra, and faces with eight equivalent Se(1)Br6 octahedra. All Rb(1)-Br(2) bond lengths are 3.89 Å. There are four shorter (3.84 Å) and four longer (3.93 Å) Rb(1)-Br(1) bond lengths. Se(1) is bonded to two equivalent Br(2) and four equivalent Br(1) atoms to form SeBr6 octahedra that share corners with six equivalent Se(1)Br6 octahedra and faces with eight equivalent Rb(1)Br12 cuboctahedra. The corner-sharing octahedra are not tilted. Both Se(1)-Br(2) bond lengths are 2.74 Å. All Se(1)-Br(1) bond lengths are 2.75 Å. There are two inequivalent Br sites. In the first Br site, Br(1) is bonded to four equivalent Rb(1) and two equivalent Se(1) atoms to form a mixture of corner, face, and edge-sharing BrRb4Se2 octahedra. The corner-sharing octahedral tilt angles range from 0-61°. In the second Br site, Br(2) is bonded to four equivalent Rb(1) and two equivalent Se(1) atoms to form a mixture of corner, face, and edge-sharing BrRb4Se2 octahedra. The corner-sharing octahedral tilt angles range from 0-61°.