Tb(Fe2Al)4 crystallizes in the tetragonal I4/mmm space group. Tb(1) is bonded in a 20-coordinate geometry to eight equivalent Fe(1), eight equivalent Fe(2), and four equivalent Al(1) atoms. There are two inequivalent Fe sites. In the first Fe site, Fe(1) is bonded in a 12-coordinate geometry to two equivalent Tb(1), two equivalent Fe(1), four equivalent Fe(2), and four equivalent Al(1) atoms. In the second Fe site, Fe(2) is bonded to two equivalent Tb(1), two equivalent Fe(2), four equivalent Fe(1), and four equivalent Al(1) atoms to form a mixture of distorted edge, face, and corner-sharing FeTb2Al4Fe6 cuboctahedra. Al(1) is bonded in a 10-coordinate geometry to one Tb(1), four equivalent Fe(1), four equivalent Fe(2), and one Al(1) atom.
Tb(Fe2Al)4 crystallizes in the tetragonal I4/mmm space group. Tb(1) is bonded in a 20-coordinate geometry to eight equivalent Fe(1), eight equivalent Fe(2), and four equivalent Al(1) atoms. All Tb(1)-Fe(1) bond lengths are 3.17 Å. All Tb(1)-Fe(2) bond lengths are 3.25 Å. All Tb(1)-Al(1) bond lengths are 2.94 Å. There are two inequivalent Fe sites. In the first Fe site, Fe(1) is bonded in a 12-coordinate geometry to two equivalent Tb(1), two equivalent Fe(1), four equivalent Fe(2), and four equivalent Al(1) atoms. Both Fe(1)-Fe(1) bond lengths are 2.80 Å. All Fe(1)-Fe(2) bond lengths are 2.47 Å. There are two shorter (2.63 Å) and two longer (2.65 Å) Fe(1)-Al(1) bond lengths. In the second Fe site, Fe(2) is bonded to two equivalent Tb(1), two equivalent Fe(2), four equivalent Fe(1), and four equivalent Al(1) atoms to form a mixture of distorted edge, face, and corner-sharing FeTb2Al4Fe6 cuboctahedra. Both Fe(2)-Fe(2) bond lengths are 2.47 Å. All Fe(2)-Al(1) bond lengths are 2.59 Å. Al(1) is bonded in a 10-coordinate geometry to one Tb(1), four equivalent Fe(1), four equivalent Fe(2), and one Al(1) atom. The Al(1)-Al(1) bond length is 2.64 Å.