Tb2FeAl3 crystallizes in the trigonal R-3m space group. Tb(1) is bonded in a 12-coordinate geometry to three equivalent Fe(1) and nine equivalent Al(1) atoms. Fe(1) is bonded to six equivalent Tb(1) and six equivalent Al(1) atoms to form FeTb6Al6 cuboctahedra that share corners with six equivalent Fe(1)Tb6Al6 cuboctahedra, corners with twelve equivalent Al(1)Tb6Al4Fe2 cuboctahedra, edges with six equivalent Fe(1)Tb6Al6 cuboctahedra, and faces with eighteen equivalent Al(1)Tb6Al4Fe2 cuboctahedra. Al(1) is bonded to six equivalent Tb(1), two equivalent Fe(1), and four equivalent Al(1) atoms to form AlTb6Al4Fe2 cuboctahedra that share corners with four equivalent Fe(1)Tb6Al6 cuboctahedra, corners with fourteen equivalent Al(1)Tb6Al4Fe2 cuboctahedra, edges with six equivalent Al(1)Tb6Al4Fe2 cuboctahedra, faces with six equivalent Fe(1)Tb6Al6 cuboctahedra, and faces with twelve equivalent Al(1)Tb6Al4Fe2 cuboctahedra.
Tb2FeAl3 crystallizes in the trigonal R-3m space group. Tb(1) is bonded in a 12-coordinate geometry to three equivalent Fe(1) and nine equivalent Al(1) atoms. All Tb(1)-Fe(1) bond lengths are 3.24 Å. There are three shorter (3.15 Å) and six longer (3.21 Å) Tb(1)-Al(1) bond lengths. Fe(1) is bonded to six equivalent Tb(1) and six equivalent Al(1) atoms to form FeTb6Al6 cuboctahedra that share corners with six equivalent Fe(1)Tb6Al6 cuboctahedra, corners with twelve equivalent Al(1)Tb6Al4Fe2 cuboctahedra, edges with six equivalent Fe(1)Tb6Al6 cuboctahedra, and faces with eighteen equivalent Al(1)Tb6Al4Fe2 cuboctahedra. All Fe(1)-Al(1) bond lengths are 2.70 Å. Al(1) is bonded to six equivalent Tb(1), two equivalent Fe(1), and four equivalent Al(1) atoms to form AlTb6Al4Fe2 cuboctahedra that share corners with four equivalent Fe(1)Tb6Al6 cuboctahedra, corners with fourteen equivalent Al(1)Tb6Al4Fe2 cuboctahedra, edges with six equivalent Al(1)Tb6Al4Fe2 cuboctahedra, faces with six equivalent Fe(1)Tb6Al6 cuboctahedra, and faces with twelve equivalent Al(1)Tb6Al4Fe2 cuboctahedra. All Al(1)-Al(1) bond lengths are 2.76 Å.