TmBi3 crystallizes in the tetragonal I4/mmm space group. Tm(1) is bonded to four equivalent Bi(2) and eight equivalent Bi(1) atoms to form TmBi12 cuboctahedra that share corners with four equivalent Tm(1)Bi12 cuboctahedra, edges with eight equivalent Tm(1)Bi12 cuboctahedra, edges with sixteen equivalent Bi(1)Tm4Bi8 cuboctahedra, faces with four equivalent Tm(1)Bi12 cuboctahedra, and faces with eight equivalent Bi(1)Tm4Bi8 cuboctahedra. There are two inequivalent Bi sites. In the first Bi site, Bi(1) is bonded to four equivalent Tm(1), four equivalent Bi(1), and four equivalent Bi(2) atoms to form distorted BiTm4Bi8 cuboctahedra that share corners with twelve equivalent Bi(1)Tm4Bi8 cuboctahedra, edges with eight equivalent Tm(1)Bi12 cuboctahedra, edges with eight equivalent Bi(1)Tm4Bi8 cuboctahedra, faces with four equivalent Tm(1)Bi12 cuboctahedra, and faces with ten equivalent Bi(1)Tm4Bi8 cuboctahedra. In the second Bi site, Bi(2) is bonded in a square co-planar geometry to four equivalent Tm(1) and eight equivalent Bi(1) atoms.
TmBi3 crystallizes in the tetragonal I4/mmm space group. Tm(1) is bonded to four equivalent Bi(2) and eight equivalent Bi(1) atoms to form TmBi12 cuboctahedra that share corners with four equivalent Tm(1)Bi12 cuboctahedra, edges with eight equivalent Tm(1)Bi12 cuboctahedra, edges with sixteen equivalent Bi(1)Tm4Bi8 cuboctahedra, faces with four equivalent Tm(1)Bi12 cuboctahedra, and faces with eight equivalent Bi(1)Tm4Bi8 cuboctahedra. All Tm(1)-Bi(2) bond lengths are 3.31 Å. All Tm(1)-Bi(1) bond lengths are 3.61 Å. There are two inequivalent Bi sites. In the first Bi site, Bi(1) is bonded to four equivalent Tm(1), four equivalent Bi(1), and four equivalent Bi(2) atoms to form distorted BiTm4Bi8 cuboctahedra that share corners with twelve equivalent Bi(1)Tm4Bi8 cuboctahedra, edges with eight equivalent Tm(1)Bi12 cuboctahedra, edges with eight equivalent Bi(1)Tm4Bi8 cuboctahedra, faces with four equivalent Tm(1)Bi12 cuboctahedra, and faces with ten equivalent Bi(1)Tm4Bi8 cuboctahedra. All Bi(1)-Bi(1) bond lengths are 3.31 Å. All Bi(1)-Bi(2) bond lengths are 3.61 Å. In the second Bi site, Bi(2) is bonded in a square co-planar geometry to four equivalent Tm(1) and eight equivalent Bi(1) atoms.