Gd2Zn17 crystallizes in the trigonal R-3m space group. Gd(1) is bonded in a 19-coordinate geometry to one Zn(4), three equivalent Zn(3), six equivalent Zn(2), and nine equivalent Zn(1) atoms. There are four inequivalent Zn sites. In the first Zn site, Zn(1) is bonded to three equivalent Gd(1), one Zn(4), two equivalent Zn(1), two equivalent Zn(3), and four equivalent Zn(2) atoms to form distorted ZnGd3Zn9 cuboctahedra that share corners with five equivalent Zn(3)Gd2Zn10 cuboctahedra, corners with eight equivalent Zn(2)Gd2Zn10 cuboctahedra, corners with ten equivalent Zn(1)Gd3Zn9 cuboctahedra, edges with two equivalent Zn(2)Gd2Zn10 cuboctahedra, edges with three equivalent Zn(3)Gd2Zn10 cuboctahedra, edges with five equivalent Zn(1)Gd3Zn9 cuboctahedra, faces with three equivalent Zn(3)Gd2Zn10 cuboctahedra, faces with seven equivalent Zn(1)Gd3Zn9 cuboctahedra, and faces with ten equivalent Zn(2)Gd2Zn10 cuboctahedra. In the second Zn site, Zn(2) is bonded to two equivalent Gd(1), two equivalent Zn(2), two equivalent Zn(3), two equivalent Zn(4), and four equivalent Zn(1) atoms to form distorted ZnGd2Zn10 cuboctahedra that share corners with four equivalent Zn(3)Gd2Zn10 cuboctahedra, corners with eight equivalent Zn(1)Gd3Zn9 cuboctahedra, corners with twelve equivalent Zn(2)Gd2Zn10 cuboctahedra,  an edgeedge with one Zn(2)Gd2Zn10 cuboctahedra, edges with two equivalent Zn(3)Gd2Zn10 cuboctahedra, edges with two equivalent Zn(1)Gd3Zn9 cuboctahedra, faces with four equivalent Zn(3)Gd2Zn10 cuboctahedra, faces with seven equivalent Zn(2)Gd2Zn10 cuboctahedra, and faces with ten equivalent Zn(1)Gd3Zn9 cuboctahedra. In the third Zn site, Zn(3) is bonded to two equivalent Gd(1), two equivalent Zn(4), four equivalent Zn(1), and four equivalent Zn(2) atoms to form ZnGd2Zn10 cuboctahedra that share corners with four equivalent Zn(3)Gd2Zn10 cuboctahedra, corners with eight equivalent Zn(2)Gd2Zn10 cuboctahedra, corners with ten equivalent Zn(1)Gd3Zn9 cuboctahedra, edges with four equivalent Zn(2)Gd2Zn10 cuboctahedra, edges with six equivalent Zn(1)Gd3Zn9 cuboctahedra, faces with four equivalent Zn(3)Gd2Zn10 cuboctahedra, faces with six equivalent Zn(1)Gd3Zn9 cuboctahedra, and faces with eight equivalent Zn(2)Gd2Zn10 cuboctahedra. In the fourth Zn site, Zn(4) is bonded in a 14-coordinate geometry to one Gd(1), one Zn(4), three equivalent Zn(1), three equivalent Zn(3), and six equivalent Zn(2) atoms.
Gd2Zn17 crystallizes in the trigonal R-3m space group. Gd(1) is bonded in a 19-coordinate geometry to one Zn(4), three equivalent Zn(3), six equivalent Zn(2), and nine equivalent Zn(1) atoms. The Gd(1)-Zn(4) bond length is 3.08 Å. All Gd(1)-Zn(3) bond lengths are 3.38 Å. All Gd(1)-Zn(2) bond lengths are 3.15 Å. There are a spread of Gd(1)-Zn(1) bond distances ranging from 3.18-3.40 Å. There are four inequivalent Zn sites. In the first Zn site, Zn(1) is bonded to three equivalent Gd(1), one Zn(4), two equivalent Zn(1), two equivalent Zn(3), and four equivalent Zn(2) atoms to form distorted ZnGd3Zn9 cuboctahedra that share corners with five equivalent Zn(3)Gd2Zn10 cuboctahedra, corners with eight equivalent Zn(2)Gd2Zn10 cuboctahedra, corners with ten equivalent Zn(1)Gd3Zn9 cuboctahedra, edges with two equivalent Zn(2)Gd2Zn10 cuboctahedra, edges with three equivalent Zn(3)Gd2Zn10 cuboctahedra, edges with five equivalent Zn(1)Gd3Zn9 cuboctahedra, faces with three equivalent Zn(3)Gd2Zn10 cuboctahedra, faces with seven equivalent Zn(1)Gd3Zn9 cuboctahedra, and faces with ten equivalent Zn(2)Gd2Zn10 cuboctahedra. The Zn(1)-Zn(4) bond length is 2.83 Å. Both Zn(1)-Zn(1) bond lengths are 2.53 Å. Both Zn(1)-Zn(3) bond lengths are 2.60 Å. There are two shorter (2.70 Å) and two longer (2.71 Å) Zn(1)-Zn(2) bond lengths. In the second Zn site, Zn(2) is bonded to two equivalent Gd(1), two equivalent Zn(2), two equivalent Zn(3), two equivalent Zn(4), and four equivalent Zn(1) atoms to form distorted ZnGd2Zn10 cuboctahedra that share corners with four equivalent Zn(3)Gd2Zn10 cuboctahedra, corners with eight equivalent Zn(1)Gd3Zn9 cuboctahedra, corners with twelve equivalent Zn(2)Gd2Zn10 cuboctahedra,  an edgeedge with one Zn(2)Gd2Zn10 cuboctahedra, edges with two equivalent Zn(3)Gd2Zn10 cuboctahedra, edges with two equivalent Zn(1)Gd3Zn9 cuboctahedra, faces with four equivalent Zn(3)Gd2Zn10 cuboctahedra, faces with seven equivalent Zn(2)Gd2Zn10 cuboctahedra, and faces with ten equivalent Zn(1)Gd3Zn9 cuboctahedra. Both Zn(2)-Zn(2) bond lengths are 2.61 Å. Both Zn(2)-Zn(3) bond lengths are 2.55 Å. Both Zn(2)-Zn(4) bond lengths are 2.91 Å. In the third Zn site, Zn(3) is bonded to two equivalent Gd(1), two equivalent Zn(4), four equivalent Zn(1), and four equivalent Zn(2) atoms to form ZnGd2Zn10 cuboctahedra that share corners with four equivalent Zn(3)Gd2Zn10 cuboctahedra, corners with eight equivalent Zn(2)Gd2Zn10 cuboctahedra, corners with ten equivalent Zn(1)Gd3Zn9 cuboctahedra, edges with four equivalent Zn(2)Gd2Zn10 cuboctahedra, edges with six equivalent Zn(1)Gd3Zn9 cuboctahedra, faces with four equivalent Zn(3)Gd2Zn10 cuboctahedra, faces with six equivalent Zn(1)Gd3Zn9 cuboctahedra, and faces with eight equivalent Zn(2)Gd2Zn10 cuboctahedra. Both Zn(3)-Zn(4) bond lengths are 2.71 Å. In the fourth Zn site, Zn(4) is bonded in a 14-coordinate geometry to one Gd(1), one Zn(4), three equivalent Zn(1), three equivalent Zn(3), and six equivalent Zn(2) atoms. The Zn(4)-Zn(4) bond length is 2.58 Å.