Tb4ZrAl15 crystallizes in the trigonal R-3m space group. There are two inequivalent Tb sites. In the first Tb site, Tb(1) is bonded to three equivalent Al(3) and nine equivalent Al(2) atoms to form TbAl12 cuboctahedra that share corners with three equivalent Tb(2)Al12 cuboctahedra, corners with six equivalent Tb(1)Al12 cuboctahedra, corners with six equivalent Al(1)Tb2Zr2Al8 cuboctahedra,  a faceface with one Zr(1)Al12 cuboctahedra, faces with three equivalent Tb(1)Al12 cuboctahedra, and faces with three equivalent Tb(2)Al12 cuboctahedra. In the second Tb site, Tb(2) is bonded to three equivalent Al(1), three equivalent Al(2), and six equivalent Al(3) atoms to form TbAl12 cuboctahedra that share corners with three equivalent Tb(1)Al12 cuboctahedra, corners with nine equivalent Tb(2)Al12 cuboctahedra, edges with six equivalent Al(1)Tb2Zr2Al8 cuboctahedra, faces with three equivalent Tb(1)Al12 cuboctahedra, faces with three equivalent Zr(1)Al12 cuboctahedra, and faces with three equivalent Al(1)Tb2Zr2Al8 cuboctahedra. Zr(1) is bonded to six equivalent Al(1) and six equivalent Al(3) atoms to form ZrAl12 cuboctahedra that share corners with six equivalent Zr(1)Al12 cuboctahedra, edges with six equivalent Al(1)Tb2Zr2Al8 cuboctahedra, faces with two equivalent Tb(1)Al12 cuboctahedra, faces with six equivalent Tb(2)Al12 cuboctahedra, and faces with six equivalent Al(1)Tb2Zr2Al8 cuboctahedra. There are three inequivalent Al sites. In the first Al site, Al(1) is bonded to two equivalent Tb(2), two equivalent Zr(1), four equivalent Al(1), and four equivalent Al(3) atoms to form distorted AlTb2Zr2Al8 cuboctahedra that share corners with four equivalent Tb(1)Al12 cuboctahedra, corners with six equivalent Al(1)Tb2Zr2Al8 cuboctahedra, edges with two equivalent Zr(1)Al12 cuboctahedra, edges with four equivalent Tb(2)Al12 cuboctahedra, edges with four equivalent Al(1)Tb2Zr2Al8 cuboctahedra, faces with two equivalent Tb(2)Al12 cuboctahedra, faces with two equivalent Zr(1)Al12 cuboctahedra, and faces with four equivalent Al(1)Tb2Zr2Al8 cuboctahedra. In the second Al site, Al(2) is bonded in a distorted square co-planar geometry to one Tb(2), three equivalent Tb(1), and two equivalent Al(3) atoms. In the third Al site, Al(3) is bonded in a 10-coordinate geometry to one Tb(1), two equivalent Tb(2), one Zr(1), two equivalent Al(1), two equivalent Al(2), and two equivalent Al(3) atoms.
Tb4ZrAl15 crystallizes in the trigonal R-3m space group. There are two inequivalent Tb sites. In the first Tb site, Tb(1) is bonded to three equivalent Al(3) and nine equivalent Al(2) atoms to form TbAl12 cuboctahedra that share corners with three equivalent Tb(2)Al12 cuboctahedra, corners with six equivalent Tb(1)Al12 cuboctahedra, corners with six equivalent Al(1)Tb2Zr2Al8 cuboctahedra,  a faceface with one Zr(1)Al12 cuboctahedra, faces with three equivalent Tb(1)Al12 cuboctahedra, and faces with three equivalent Tb(2)Al12 cuboctahedra. All Tb(1)-Al(3) bond lengths are 3.06 Å. There are three shorter (3.02 Å) and six longer (3.04 Å) Tb(1)-Al(2) bond lengths. In the second Tb site, Tb(2) is bonded to three equivalent Al(1), three equivalent Al(2), and six equivalent Al(3) atoms to form TbAl12 cuboctahedra that share corners with three equivalent Tb(1)Al12 cuboctahedra, corners with nine equivalent Tb(2)Al12 cuboctahedra, edges with six equivalent Al(1)Tb2Zr2Al8 cuboctahedra, faces with three equivalent Tb(1)Al12 cuboctahedra, faces with three equivalent Zr(1)Al12 cuboctahedra, and faces with three equivalent Al(1)Tb2Zr2Al8 cuboctahedra. All Tb(2)-Al(1) bond lengths are 2.97 Å. All Tb(2)-Al(2) bond lengths are 3.01 Å. All Tb(2)-Al(3) bond lengths are 3.04 Å. Zr(1) is bonded to six equivalent Al(1) and six equivalent Al(3) atoms to form ZrAl12 cuboctahedra that share corners with six equivalent Zr(1)Al12 cuboctahedra, edges with six equivalent Al(1)Tb2Zr2Al8 cuboctahedra, faces with two equivalent Tb(1)Al12 cuboctahedra, faces with six equivalent Tb(2)Al12 cuboctahedra, and faces with six equivalent Al(1)Tb2Zr2Al8 cuboctahedra. All Zr(1)-Al(1) bond lengths are 3.03 Å. All Zr(1)-Al(3) bond lengths are 3.01 Å. There are three inequivalent Al sites. In the first Al site, Al(1) is bonded to two equivalent Tb(2), two equivalent Zr(1), four equivalent Al(1), and four equivalent Al(3) atoms to form distorted AlTb2Zr2Al8 cuboctahedra that share corners with four equivalent Tb(1)Al12 cuboctahedra, corners with six equivalent Al(1)Tb2Zr2Al8 cuboctahedra, edges with two equivalent Zr(1)Al12 cuboctahedra, edges with four equivalent Tb(2)Al12 cuboctahedra, edges with four equivalent Al(1)Tb2Zr2Al8 cuboctahedra, faces with two equivalent Tb(2)Al12 cuboctahedra, faces with two equivalent Zr(1)Al12 cuboctahedra, and faces with four equivalent Al(1)Tb2Zr2Al8 cuboctahedra. All Al(1)-Al(1) bond lengths are 3.03 Å. All Al(1)-Al(3) bond lengths are 2.87 Å. In the second Al site, Al(2) is bonded in a distorted square co-planar geometry to one Tb(2), three equivalent Tb(1), and two equivalent Al(3) atoms. Both Al(2)-Al(3) bond lengths are 3.00 Å. In the third Al site, Al(3) is bonded in a 10-coordinate geometry to one Tb(1), two equivalent Tb(2), one Zr(1), two equivalent Al(1), two equivalent Al(2), and two equivalent Al(3) atoms. Both Al(3)-Al(3) bond lengths are 2.76 Å.