Tm(CrAl2)4 crystallizes in the tetragonal I4/mmm space group. Tm(1) is bonded in a 20-coordinate geometry to eight equivalent Cr(1), four equivalent Al(2), and eight equivalent Al(1) atoms. Cr(1) is bonded to two equivalent Tm(1), two equivalent Cr(1), four equivalent Al(1), and four equivalent Al(2) atoms to form distorted CrTm2Al8Cr2 cuboctahedra that share corners with eight equivalent Al(1)Tm2Al6Cr4 cuboctahedra, corners with ten equivalent Cr(1)Tm2Al8Cr2 cuboctahedra, edges with four equivalent Cr(1)Tm2Al8Cr2 cuboctahedra, edges with four equivalent Al(1)Tm2Al6Cr4 cuboctahedra, faces with six equivalent Cr(1)Tm2Al8Cr2 cuboctahedra, and faces with eight equivalent Al(1)Tm2Al6Cr4 cuboctahedra. There are two inequivalent Al sites. In the first Al site, Al(1) is bonded to two equivalent Tm(1), four equivalent Cr(1), two equivalent Al(1), and four equivalent Al(2) atoms to form distorted AlTm2Al6Cr4 cuboctahedra that share corners with eight equivalent Cr(1)Tm2Al8Cr2 cuboctahedra, corners with ten equivalent Al(1)Tm2Al6Cr4 cuboctahedra, edges with three equivalent Al(1)Tm2Al6Cr4 cuboctahedra, edges with four equivalent Cr(1)Tm2Al8Cr2 cuboctahedra, faces with seven equivalent Al(1)Tm2Al6Cr4 cuboctahedra, and faces with eight equivalent Cr(1)Tm2Al8Cr2 cuboctahedra. In the second Al site, Al(2) is bonded in a 10-coordinate geometry to one Tm(1), four equivalent Cr(1), one Al(2), and four equivalent Al(1) atoms.
Tm(CrAl2)4 crystallizes in the tetragonal I4/mmm space group. Tm(1) is bonded in a 20-coordinate geometry to eight equivalent Cr(1), four equivalent Al(2), and eight equivalent Al(1) atoms. All Tm(1)-Cr(1) bond lengths are 3.39 Å. All Tm(1)-Al(2) bond lengths are 2.98 Å. All Tm(1)-Al(1) bond lengths are 3.20 Å. Cr(1) is bonded to two equivalent Tm(1), two equivalent Cr(1), four equivalent Al(1), and four equivalent Al(2) atoms to form distorted CrTm2Al8Cr2 cuboctahedra that share corners with eight equivalent Al(1)Tm2Al6Cr4 cuboctahedra, corners with ten equivalent Cr(1)Tm2Al8Cr2 cuboctahedra, edges with four equivalent Cr(1)Tm2Al8Cr2 cuboctahedra, edges with four equivalent Al(1)Tm2Al6Cr4 cuboctahedra, faces with six equivalent Cr(1)Tm2Al8Cr2 cuboctahedra, and faces with eight equivalent Al(1)Tm2Al6Cr4 cuboctahedra. Both Cr(1)-Cr(1) bond lengths are 2.53 Å. All Cr(1)-Al(1) bond lengths are 2.57 Å. All Cr(1)-Al(2) bond lengths are 2.67 Å. There are two inequivalent Al sites. In the first Al site, Al(1) is bonded to two equivalent Tm(1), four equivalent Cr(1), two equivalent Al(1), and four equivalent Al(2) atoms to form distorted AlTm2Al6Cr4 cuboctahedra that share corners with eight equivalent Cr(1)Tm2Al8Cr2 cuboctahedra, corners with ten equivalent Al(1)Tm2Al6Cr4 cuboctahedra, edges with three equivalent Al(1)Tm2Al6Cr4 cuboctahedra, edges with four equivalent Cr(1)Tm2Al8Cr2 cuboctahedra, faces with seven equivalent Al(1)Tm2Al6Cr4 cuboctahedra, and faces with eight equivalent Cr(1)Tm2Al8Cr2 cuboctahedra. Both Al(1)-Al(1) bond lengths are 2.78 Å. There are two shorter (2.72 Å) and two longer (2.88 Å) Al(1)-Al(2) bond lengths. In the second Al site, Al(2) is bonded in a 10-coordinate geometry to one Tm(1), four equivalent Cr(1), one Al(2), and four equivalent Al(1) atoms. The Al(2)-Al(2) bond length is 2.92 Å.