Nd2Fe17N2 crystallizes in the monoclinic C2/m space group. Nd(1) is bonded in a distorted bent 120 degrees geometry to one Fe(3), one Fe(7), two equivalent Fe(1), two equivalent Fe(4), three equivalent Fe(5), and two equivalent N(1) atoms. There are seven inequivalent Fe sites. In the first Fe site, Fe(1) is bonded in a 12-coordinate geometry to two equivalent Nd(1), two equivalent Fe(2), two equivalent Fe(4), two equivalent Fe(5), two equivalent Fe(6), and two equivalent Fe(7) atoms. In the second Fe site, Fe(2) is bonded in a single-bond geometry to one Fe(1), one Fe(3), one Fe(4), one Fe(5), two equivalent Fe(7), and one N(1) atom. In the third Fe site, Fe(3) is bonded to two equivalent Nd(1), two equivalent Fe(7), four equivalent Fe(2), and four equivalent Fe(6) atoms to form FeNd2Fe10 cuboctahedra that share corners with four equivalent Fe(4)Nd2Fe10 cuboctahedra, corners with six equivalent Fe(5)Nd3Fe9 cuboctahedra, edges with two equivalent Fe(5)Nd3Fe9 cuboctahedra, faces with two equivalent Fe(5)Nd3Fe9 cuboctahedra, faces with four equivalent Fe(4)Nd2Fe10 cuboctahedra, and faces with four equivalent N(1)Nd2Fe4 octahedra. In the fourth Fe site, Fe(4) is bonded to two equivalent Nd(1), two equivalent Fe(1), two equivalent Fe(2), two equivalent Fe(5), two equivalent Fe(6), and two equivalent Fe(7) atoms to form FeNd2Fe10 cuboctahedra that share corners with two equivalent Fe(3)Nd2Fe10 cuboctahedra, corners with two equivalent Fe(4)Nd2Fe10 cuboctahedra, corners with two equivalent Fe(5)Nd3Fe9 cuboctahedra, corners with two equivalent N(1)Nd2Fe4 octahedra, edges with two equivalent Fe(5)Nd3Fe9 cuboctahedra, faces with two equivalent Fe(3)Nd2Fe10 cuboctahedra, faces with two equivalent Fe(4)Nd2Fe10 cuboctahedra, faces with two equivalent Fe(5)Nd3Fe9 cuboctahedra, and faces with two equivalent N(1)Nd2Fe4 octahedra. The corner-sharing octahedral tilt angles are 44°. In the fifth Fe site, Fe(5) is bonded to three equivalent Nd(1), one Fe(7), two equivalent Fe(1), two equivalent Fe(2), two equivalent Fe(4), and two equivalent Fe(6) atoms to form FeNd3Fe9 cuboctahedra that share corners with two equivalent Fe(4)Nd2Fe10 cuboctahedra, corners with three equivalent Fe(3)Nd2Fe10 cuboctahedra, corners with four equivalent Fe(5)Nd3Fe9 cuboctahedra, corners with four equivalent N(1)Nd2Fe4 octahedra,  an edgeedge with one Fe(3)Nd2Fe10 cuboctahedra,  an edgeedge with one Fe(5)Nd3Fe9 cuboctahedra, edges with two equivalent Fe(4)Nd2Fe10 cuboctahedra,  a faceface with one Fe(3)Nd2Fe10 cuboctahedra,  a faceface with one Fe(5)Nd3Fe9 cuboctahedra, faces with two equivalent Fe(4)Nd2Fe10 cuboctahedra, and faces with two equivalent N(1)Nd2Fe4 octahedra. The corner-sharing octahedral tilt angles range from 64-69°. In the sixth Fe site, Fe(6) is bonded in a single-bond geometry to one Fe(1), one Fe(3), one Fe(4), one Fe(5), one Fe(7), and one N(1) atom. In the seventh Fe site, Fe(7) is bonded in a 14-coordinate geometry to one Nd(1), one Fe(3), one Fe(5), one Fe(7), two equivalent Fe(1), two equivalent Fe(4), two equivalent Fe(6), and four equivalent Fe(2) atoms. N(1) is bonded to two equivalent Nd(1), two equivalent Fe(2), and two equivalent Fe(6) atoms to form NNd2Fe4 octahedra that share corners with two equivalent Fe(4)Nd2Fe10 cuboctahedra, corners with four equivalent Fe(5)Nd3Fe9 cuboctahedra, corners with two equivalent N(1)Nd2Fe4 octahedra, faces with two equivalent Fe(3)Nd2Fe10 cuboctahedra, faces with two equivalent Fe(4)Nd2Fe10 cuboctahedra, and faces with two equivalent Fe(5)Nd3Fe9 cuboctahedra. The corner-sharing octahedral tilt angles are 61°.
Nd2Fe17N2 crystallizes in the monoclinic C2/m space group. Nd(1) is bonded in a distorted bent 120 degrees geometry to one Fe(3), one Fe(7), two equivalent Fe(1), two equivalent Fe(4), three equivalent Fe(5), and two equivalent N(1) atoms. The Nd(1)-Fe(3) bond length is 3.34 Å. The Nd(1)-Fe(7) bond length is 3.09 Å. Both Nd(1)-Fe(1) bond lengths are 3.14 Å. Both Nd(1)-Fe(4) bond lengths are 3.34 Å. There are a spread of Nd(1)-Fe(5) bond distances ranging from 3.12-3.38 Å. Both Nd(1)-N(1) bond lengths are 2.52 Å. There are seven inequivalent Fe sites. In the first Fe site, Fe(1) is bonded in a 12-coordinate geometry to two equivalent Nd(1), two equivalent Fe(2), two equivalent Fe(4), two equivalent Fe(5), two equivalent Fe(6), and two equivalent Fe(7) atoms. Both Fe(1)-Fe(2) bond lengths are 2.47 Å. Both Fe(1)-Fe(4) bond lengths are 2.44 Å. Both Fe(1)-Fe(5) bond lengths are 2.67 Å. Both Fe(1)-Fe(6) bond lengths are 2.56 Å. Both Fe(1)-Fe(7) bond lengths are 2.72 Å. In the second Fe site, Fe(2) is bonded in a single-bond geometry to one Fe(1), one Fe(3), one Fe(4), one Fe(5), two equivalent Fe(7), and one N(1) atom. The Fe(2)-Fe(3) bond length is 2.45 Å. The Fe(2)-Fe(4) bond length is 2.45 Å. The Fe(2)-Fe(5) bond length is 2.59 Å. There is one shorter (2.73 Å) and one longer (2.74 Å) Fe(2)-Fe(7) bond length. The Fe(2)-N(1) bond length is 1.89 Å. In the third Fe site, Fe(3) is bonded to two equivalent Nd(1), two equivalent Fe(7), four equivalent Fe(2), and four equivalent Fe(6) atoms to form FeNd2Fe10 cuboctahedra that share corners with four equivalent Fe(4)Nd2Fe10 cuboctahedra, corners with six equivalent Fe(5)Nd3Fe9 cuboctahedra, edges with two equivalent Fe(5)Nd3Fe9 cuboctahedra, faces with two equivalent Fe(5)Nd3Fe9 cuboctahedra, faces with four equivalent Fe(4)Nd2Fe10 cuboctahedra, and faces with four equivalent N(1)Nd2Fe4 octahedra. Both Fe(3)-Fe(7) bond lengths are 2.69 Å. All Fe(3)-Fe(6) bond lengths are 2.50 Å. In the fourth Fe site, Fe(4) is bonded to two equivalent Nd(1), two equivalent Fe(1), two equivalent Fe(2), two equivalent Fe(5), two equivalent Fe(6), and two equivalent Fe(7) atoms to form FeNd2Fe10 cuboctahedra that share corners with two equivalent Fe(3)Nd2Fe10 cuboctahedra, corners with two equivalent Fe(4)Nd2Fe10 cuboctahedra, corners with two equivalent Fe(5)Nd3Fe9 cuboctahedra, corners with two equivalent N(1)Nd2Fe4 octahedra, edges with two equivalent Fe(5)Nd3Fe9 cuboctahedra, faces with two equivalent Fe(3)Nd2Fe10 cuboctahedra, faces with two equivalent Fe(4)Nd2Fe10 cuboctahedra, faces with two equivalent Fe(5)Nd3Fe9 cuboctahedra, and faces with two equivalent N(1)Nd2Fe4 octahedra. The corner-sharing octahedral tilt angles are 44°. Both Fe(4)-Fe(5) bond lengths are 2.49 Å. Both Fe(4)-Fe(6) bond lengths are 2.47 Å. Both Fe(4)-Fe(7) bond lengths are 2.66 Å. In the fifth Fe site, Fe(5) is bonded to three equivalent Nd(1), one Fe(7), two equivalent Fe(1), two equivalent Fe(2), two equivalent Fe(4), and two equivalent Fe(6) atoms to form FeNd3Fe9 cuboctahedra that share corners with two equivalent Fe(4)Nd2Fe10 cuboctahedra, corners with three equivalent Fe(3)Nd2Fe10 cuboctahedra, corners with four equivalent Fe(5)Nd3Fe9 cuboctahedra, corners with four equivalent N(1)Nd2Fe4 octahedra,  an edgeedge with one Fe(3)Nd2Fe10 cuboctahedra,  an edgeedge with one Fe(5)Nd3Fe9 cuboctahedra, edges with two equivalent Fe(4)Nd2Fe10 cuboctahedra,  a faceface with one Fe(3)Nd2Fe10 cuboctahedra,  a faceface with one Fe(5)Nd3Fe9 cuboctahedra, faces with two equivalent Fe(4)Nd2Fe10 cuboctahedra, and faces with two equivalent N(1)Nd2Fe4 octahedra. The corner-sharing octahedral tilt angles range from 64-69°. The Fe(5)-Fe(7) bond length is 2.67 Å. Both Fe(5)-Fe(6) bond lengths are 2.59 Å. In the sixth Fe site, Fe(6) is bonded in a single-bond geometry to one Fe(1), one Fe(3), one Fe(4), one Fe(5), one Fe(7), and one N(1) atom. The Fe(6)-Fe(7) bond length is 2.66 Å. The Fe(6)-N(1) bond length is 1.93 Å. In the seventh Fe site, Fe(7) is bonded in a 14-coordinate geometry to one Nd(1), one Fe(3), one Fe(5), one Fe(7), two equivalent Fe(1), two equivalent Fe(4), two equivalent Fe(6), and four equivalent Fe(2) atoms. The Fe(7)-Fe(7) bond length is 2.36 Å. N(1) is bonded to two equivalent Nd(1), two equivalent Fe(2), and two equivalent Fe(6) atoms to form NNd2Fe4 octahedra that share corners with two equivalent Fe(4)Nd2Fe10 cuboctahedra, corners with four equivalent Fe(5)Nd3Fe9 cuboctahedra, corners with two equivalent N(1)Nd2Fe4 octahedra, faces with two equivalent Fe(3)Nd2Fe10 cuboctahedra, faces with two equivalent Fe(4)Nd2Fe10 cuboctahedra, and faces with two equivalent Fe(5)Nd3Fe9 cuboctahedra. The corner-sharing octahedral tilt angles are 61°.