Rb3Tm2Cu4Br13 crystallizes in the cubic Pn-3 space group. Rb(1) is bonded in a 8-coordinate geometry to eight equivalent Br(1) atoms. Tm(1) is bonded to six equivalent Br(1) atoms to form TmBr6 octahedra that share corners with six equivalent Cu(1)Br4 tetrahedra. Cu(1) is bonded to one Br(2) and three equivalent Br(1) atoms to form CuBr4 tetrahedra that share corners with three equivalent Tm(1)Br6 octahedra and corners with three equivalent Cu(1)Br4 tetrahedra. The corner-sharing octahedral tilt angles are 57°. There are two inequivalent Br sites. In the first Br site, Br(1) is bonded in a 4-coordinate geometry to two equivalent Rb(1), one Tm(1), and one Cu(1) atom. In the second Br site, Br(2) is bonded in a tetrahedral geometry to four equivalent Cu(1) atoms.
Rb3Tm2Cu4Br13 crystallizes in the cubic Pn-3 space group. Rb(1) is bonded in a 8-coordinate geometry to eight equivalent Br(1) atoms. There are four shorter (3.58 Å) and four longer (3.83 Å) Rb(1)-Br(1) bond lengths. Tm(1) is bonded to six equivalent Br(1) atoms to form TmBr6 octahedra that share corners with six equivalent Cu(1)Br4 tetrahedra. All Tm(1)-Br(1) bond lengths are 2.76 Å. Cu(1) is bonded to one Br(2) and three equivalent Br(1) atoms to form CuBr4 tetrahedra that share corners with three equivalent Tm(1)Br6 octahedra and corners with three equivalent Cu(1)Br4 tetrahedra. The corner-sharing octahedral tilt angles are 57°. The Cu(1)-Br(2) bond length is 2.43 Å. All Cu(1)-Br(1) bond lengths are 2.45 Å. There are two inequivalent Br sites. In the first Br site, Br(1) is bonded in a 4-coordinate geometry to two equivalent Rb(1), one Tm(1), and one Cu(1) atom. In the second Br site, Br(2) is bonded in a tetrahedral geometry to four equivalent Cu(1) atoms.