RbCoBr3 crystallizes in the trigonal P3c1 space group. Rb(1) is bonded to four equivalent Br(1), four equivalent Br(2), and four equivalent Br(3) atoms to form distorted RbBr12 cuboctahedra that share corners with six equivalent Rb(1)Br12 cuboctahedra, corners with two equivalent Co(1)Br6 octahedra, corners with two equivalent Co(2)Br6 octahedra, corners with two equivalent Co(3)Br6 octahedra, faces with eight equivalent Rb(1)Br12 cuboctahedra, faces with two equivalent Co(1)Br6 octahedra, faces with two equivalent Co(2)Br6 octahedra, and faces with two equivalent Co(3)Br6 octahedra. The corner-sharing octahedral tilt angles range from 15-19°. There are three inequivalent Co sites. In the first Co site, Co(1) is bonded to six equivalent Br(2) atoms to form CoBr6 octahedra that share corners with six equivalent Rb(1)Br12 cuboctahedra, faces with six equivalent Rb(1)Br12 cuboctahedra, and faces with two equivalent Co(1)Br6 octahedra. In the second Co site, Co(2) is bonded to six equivalent Br(3) atoms to form CoBr6 octahedra that share corners with six equivalent Rb(1)Br12 cuboctahedra, faces with six equivalent Rb(1)Br12 cuboctahedra, and faces with two equivalent Co(2)Br6 octahedra. In the third Co site, Co(3) is bonded to six equivalent Br(1) atoms to form CoBr6 octahedra that share corners with six equivalent Rb(1)Br12 cuboctahedra, faces with six equivalent Rb(1)Br12 cuboctahedra, and faces with two equivalent Co(3)Br6 octahedra. There are three inequivalent Br sites. In the first Br site, Br(1) is bonded in a 2-coordinate geometry to four equivalent Rb(1) and two equivalent Co(3) atoms. In the second Br site, Br(2) is bonded in a 2-coordinate geometry to four equivalent Rb(1) and two equivalent Co(1) atoms. In the third Br site, Br(3) is bonded to four equivalent Rb(1) and two equivalent Co(2) atoms to form a mixture of distorted corner and face-sharing BrRb4Co2 octahedra. The corner-sharing octahedral tilt angles range from 0-71°.
RbCoBr3 crystallizes in the trigonal P3c1 space group. Rb(1) is bonded to four equivalent Br(1), four equivalent Br(2), and four equivalent Br(3) atoms to form distorted RbBr12 cuboctahedra that share corners with six equivalent Rb(1)Br12 cuboctahedra, corners with two equivalent Co(1)Br6 octahedra, corners with two equivalent Co(2)Br6 octahedra, corners with two equivalent Co(3)Br6 octahedra, faces with eight equivalent Rb(1)Br12 cuboctahedra, faces with two equivalent Co(1)Br6 octahedra, faces with two equivalent Co(2)Br6 octahedra, and faces with two equivalent Co(3)Br6 octahedra. The corner-sharing octahedral tilt angles range from 15-19°. There are a spread of Rb(1)-Br(1) bond distances ranging from 3.71-4.00 Å. There are a spread of Rb(1)-Br(2) bond distances ranging from 3.69-4.02 Å. There are a spread of Rb(1)-Br(3) bond distances ranging from 3.71-3.90 Å. There are three inequivalent Co sites. In the first Co site, Co(1) is bonded to six equivalent Br(2) atoms to form CoBr6 octahedra that share corners with six equivalent Rb(1)Br12 cuboctahedra, faces with six equivalent Rb(1)Br12 cuboctahedra, and faces with two equivalent Co(1)Br6 octahedra. There are three shorter (2.57 Å) and three longer (2.59 Å) Co(1)-Br(2) bond lengths. In the second Co site, Co(2) is bonded to six equivalent Br(3) atoms to form CoBr6 octahedra that share corners with six equivalent Rb(1)Br12 cuboctahedra, faces with six equivalent Rb(1)Br12 cuboctahedra, and faces with two equivalent Co(2)Br6 octahedra. All Co(2)-Br(3) bond lengths are 2.58 Å. In the third Co site, Co(3) is bonded to six equivalent Br(1) atoms to form CoBr6 octahedra that share corners with six equivalent Rb(1)Br12 cuboctahedra, faces with six equivalent Rb(1)Br12 cuboctahedra, and faces with two equivalent Co(3)Br6 octahedra. There are three shorter (2.57 Å) and three longer (2.58 Å) Co(3)-Br(1) bond lengths. There are three inequivalent Br sites. In the first Br site, Br(1) is bonded in a 2-coordinate geometry to four equivalent Rb(1) and two equivalent Co(3) atoms. In the second Br site, Br(2) is bonded in a 2-coordinate geometry to four equivalent Rb(1) and two equivalent Co(1) atoms. In the third Br site, Br(3) is bonded to four equivalent Rb(1) and two equivalent Co(2) atoms to form a mixture of distorted corner and face-sharing BrRb4Co2 octahedra. The corner-sharing octahedral tilt angles range from 0-71°.