Nd2Fe17 crystallizes in the trigonal R-3m space group. Nd(1) is bonded in a 19-coordinate geometry to one Fe(4), three equivalent Fe(1), six equivalent Fe(2), and nine equivalent Fe(3) atoms. There are four inequivalent Fe sites. In the first Fe site, Fe(1) is bonded to two equivalent Nd(1), two equivalent Fe(4), four equivalent Fe(2), and four equivalent Fe(3) atoms to form FeNd2Fe10 cuboctahedra that share corners with four equivalent Fe(1)Nd2Fe10 cuboctahedra, corners with eight equivalent Fe(2)Nd2Fe10 cuboctahedra, corners with ten equivalent Fe(3)Nd3Fe9 cuboctahedra, edges with four equivalent Fe(2)Nd2Fe10 cuboctahedra, edges with six equivalent Fe(3)Nd3Fe9 cuboctahedra, faces with four equivalent Fe(1)Nd2Fe10 cuboctahedra, faces with six equivalent Fe(3)Nd3Fe9 cuboctahedra, and faces with eight equivalent Fe(2)Nd2Fe10 cuboctahedra. In the second Fe site, Fe(2) is bonded to two equivalent Nd(1), two equivalent Fe(1), two equivalent Fe(2), two equivalent Fe(4), and four equivalent Fe(3) atoms to form distorted FeNd2Fe10 cuboctahedra that share corners with four equivalent Fe(1)Nd2Fe10 cuboctahedra, corners with eight equivalent Fe(3)Nd3Fe9 cuboctahedra, corners with twelve equivalent Fe(2)Nd2Fe10 cuboctahedra,  an edgeedge with one Fe(2)Nd2Fe10 cuboctahedra, edges with two equivalent Fe(1)Nd2Fe10 cuboctahedra, edges with two equivalent Fe(3)Nd3Fe9 cuboctahedra, faces with four equivalent Fe(1)Nd2Fe10 cuboctahedra, faces with seven equivalent Fe(2)Nd2Fe10 cuboctahedra, and faces with ten equivalent Fe(3)Nd3Fe9 cuboctahedra. In the third Fe site, Fe(3) is bonded to three equivalent Nd(1), one Fe(4), two equivalent Fe(1), two equivalent Fe(3), and four equivalent Fe(2) atoms to form FeNd3Fe9 cuboctahedra that share corners with five equivalent Fe(1)Nd2Fe10 cuboctahedra, corners with eight equivalent Fe(2)Nd2Fe10 cuboctahedra, corners with ten equivalent Fe(3)Nd3Fe9 cuboctahedra, edges with two equivalent Fe(2)Nd2Fe10 cuboctahedra, edges with three equivalent Fe(1)Nd2Fe10 cuboctahedra, edges with five equivalent Fe(3)Nd3Fe9 cuboctahedra, faces with three equivalent Fe(1)Nd2Fe10 cuboctahedra, faces with seven equivalent Fe(3)Nd3Fe9 cuboctahedra, and faces with ten equivalent Fe(2)Nd2Fe10 cuboctahedra. In the fourth Fe site, Fe(4) is bonded in a 14-coordinate geometry to one Nd(1), one Fe(4), three equivalent Fe(1), three equivalent Fe(3), and six equivalent Fe(2) atoms.
Nd2Fe17 crystallizes in the trigonal R-3m space group. Nd(1) is bonded in a 19-coordinate geometry to one Fe(4), three equivalent Fe(1), six equivalent Fe(2), and nine equivalent Fe(3) atoms. The Nd(1)-Fe(4) bond length is 3.05 Å. All Nd(1)-Fe(1) bond lengths are 3.30 Å. All Nd(1)-Fe(2) bond lengths are 3.07 Å. There are a spread of Nd(1)-Fe(3) bond distances ranging from 3.11-3.26 Å. There are four inequivalent Fe sites. In the first Fe site, Fe(1) is bonded to two equivalent Nd(1), two equivalent Fe(4), four equivalent Fe(2), and four equivalent Fe(3) atoms to form FeNd2Fe10 cuboctahedra that share corners with four equivalent Fe(1)Nd2Fe10 cuboctahedra, corners with eight equivalent Fe(2)Nd2Fe10 cuboctahedra, corners with ten equivalent Fe(3)Nd3Fe9 cuboctahedra, edges with four equivalent Fe(2)Nd2Fe10 cuboctahedra, edges with six equivalent Fe(3)Nd3Fe9 cuboctahedra, faces with four equivalent Fe(1)Nd2Fe10 cuboctahedra, faces with six equivalent Fe(3)Nd3Fe9 cuboctahedra, and faces with eight equivalent Fe(2)Nd2Fe10 cuboctahedra. Both Fe(1)-Fe(4) bond lengths are 2.63 Å. All Fe(1)-Fe(2) bond lengths are 2.44 Å. All Fe(1)-Fe(3) bond lengths are 2.47 Å. In the second Fe site, Fe(2) is bonded to two equivalent Nd(1), two equivalent Fe(1), two equivalent Fe(2), two equivalent Fe(4), and four equivalent Fe(3) atoms to form distorted FeNd2Fe10 cuboctahedra that share corners with four equivalent Fe(1)Nd2Fe10 cuboctahedra, corners with eight equivalent Fe(3)Nd3Fe9 cuboctahedra, corners with twelve equivalent Fe(2)Nd2Fe10 cuboctahedra,  an edgeedge with one Fe(2)Nd2Fe10 cuboctahedra, edges with two equivalent Fe(1)Nd2Fe10 cuboctahedra, edges with two equivalent Fe(3)Nd3Fe9 cuboctahedra, faces with four equivalent Fe(1)Nd2Fe10 cuboctahedra, faces with seven equivalent Fe(2)Nd2Fe10 cuboctahedra, and faces with ten equivalent Fe(3)Nd3Fe9 cuboctahedra. Both Fe(2)-Fe(2) bond lengths are 2.48 Å. Both Fe(2)-Fe(4) bond lengths are 2.76 Å. There are two shorter (2.54 Å) and two longer (2.67 Å) Fe(2)-Fe(3) bond lengths. In the third Fe site, Fe(3) is bonded to three equivalent Nd(1), one Fe(4), two equivalent Fe(1), two equivalent Fe(3), and four equivalent Fe(2) atoms to form FeNd3Fe9 cuboctahedra that share corners with five equivalent Fe(1)Nd2Fe10 cuboctahedra, corners with eight equivalent Fe(2)Nd2Fe10 cuboctahedra, corners with ten equivalent Fe(3)Nd3Fe9 cuboctahedra, edges with two equivalent Fe(2)Nd2Fe10 cuboctahedra, edges with three equivalent Fe(1)Nd2Fe10 cuboctahedra, edges with five equivalent Fe(3)Nd3Fe9 cuboctahedra, faces with three equivalent Fe(1)Nd2Fe10 cuboctahedra, faces with seven equivalent Fe(3)Nd3Fe9 cuboctahedra, and faces with ten equivalent Fe(2)Nd2Fe10 cuboctahedra. The Fe(3)-Fe(4) bond length is 2.65 Å. Both Fe(3)-Fe(3) bond lengths are 2.51 Å. In the fourth Fe site, Fe(4) is bonded in a 14-coordinate geometry to one Nd(1), one Fe(4), three equivalent Fe(1), three equivalent Fe(3), and six equivalent Fe(2) atoms. The Fe(4)-Fe(4) bond length is 2.42 Å.