Cs3TmCl6 crystallizes in the cubic Fm-3m space group. There are two inequivalent Cs sites. In the first Cs site, Cs(1) is bonded to twelve equivalent Cl(1) atoms to form distorted CsCl12 cuboctahedra that share corners with twelve equivalent Cs(1)Cl12 cuboctahedra, faces with six equivalent Cs(1)Cl12 cuboctahedra, faces with four equivalent Cs(2)Cl6 octahedra, and faces with four equivalent Tm(1)Cl6 octahedra. In the second Cs site, Cs(2) is bonded to six equivalent Cl(1) atoms to form CsCl6 octahedra that share corners with six equivalent Tm(1)Cl6 octahedra and faces with eight equivalent Cs(1)Cl12 cuboctahedra. The corner-sharing octahedra are not tilted. Tm(1) is bonded to six equivalent Cl(1) atoms to form TmCl6 octahedra that share corners with six equivalent Cs(2)Cl6 octahedra and faces with eight equivalent Cs(1)Cl12 cuboctahedra. The corner-sharing octahedra are not tilted. Cl(1) is bonded in a distorted linear geometry to one Cs(2), four equivalent Cs(1), and one Tm(1) atom.
Cs3TmCl6 crystallizes in the cubic Fm-3m space group. There are two inequivalent Cs sites. In the first Cs site, Cs(1) is bonded to twelve equivalent Cl(1) atoms to form distorted CsCl12 cuboctahedra that share corners with twelve equivalent Cs(1)Cl12 cuboctahedra, faces with six equivalent Cs(1)Cl12 cuboctahedra, faces with four equivalent Cs(2)Cl6 octahedra, and faces with four equivalent Tm(1)Cl6 octahedra. All Cs(1)-Cl(1) bond lengths are 4.18 Å. In the second Cs site, Cs(2) is bonded to six equivalent Cl(1) atoms to form CsCl6 octahedra that share corners with six equivalent Tm(1)Cl6 octahedra and faces with eight equivalent Cs(1)Cl12 cuboctahedra. The corner-sharing octahedra are not tilted. All Cs(2)-Cl(1) bond lengths are 3.28 Å. Tm(1) is bonded to six equivalent Cl(1) atoms to form TmCl6 octahedra that share corners with six equivalent Cs(2)Cl6 octahedra and faces with eight equivalent Cs(1)Cl12 cuboctahedra. The corner-sharing octahedra are not tilted. All Tm(1)-Cl(1) bond lengths are 2.61 Å. Cl(1) is bonded in a distorted linear geometry to one Cs(2), four equivalent Cs(1), and one Tm(1) atom.