Nd2TiFe16 crystallizes in the trigonal R3m space group. There are two inequivalent Nd sites. In the first Nd site, Nd(1) is bonded in a 19-coordinate geometry to one Fe(5), three equivalent Fe(1), three equivalent Fe(4), six equivalent Fe(2), and six equivalent Fe(3) atoms. In the second Nd site, Nd(2) is bonded in a 19-coordinate geometry to one Ti(1), three equivalent Fe(2), three equivalent Fe(4), six equivalent Fe(1), and six equivalent Fe(3) atoms. Ti(1) is bonded in a 14-coordinate geometry to one Nd(2), one Fe(5), three equivalent Fe(1), three equivalent Fe(4), and six equivalent Fe(3) atoms. There are five inequivalent Fe sites. In the first Fe site, Fe(1) is bonded to one Nd(1), two equivalent Nd(2), one Ti(1), two equivalent Fe(2), two equivalent Fe(4), and four equivalent Fe(3) atoms to form FeNd3TiFe8 cuboctahedra that share corners with two equivalent Fe(1)Nd3TiFe8 cuboctahedra, corners with five equivalent Fe(4)Nd2TiFe9 cuboctahedra, corners with eight equivalent Fe(2)Nd3Fe9 cuboctahedra,  an edgeedge with one Fe(2)Nd3Fe9 cuboctahedra, edges with three equivalent Fe(4)Nd2TiFe9 cuboctahedra, edges with four equivalent Fe(1)Nd3TiFe8 cuboctahedra, faces with three equivalent Fe(4)Nd2TiFe9 cuboctahedra, faces with three equivalent Fe(2)Nd3Fe9 cuboctahedra, and faces with four equivalent Fe(1)Nd3TiFe8 cuboctahedra. In the second Fe site, Fe(2) is bonded to one Nd(2), two equivalent Nd(1), one Fe(5), two equivalent Fe(1), two equivalent Fe(4), and four equivalent Fe(3) atoms to form FeNd3Fe9 cuboctahedra that share corners with two equivalent Fe(2)Nd3Fe9 cuboctahedra, corners with five equivalent Fe(4)Nd2TiFe9 cuboctahedra, corners with eight equivalent Fe(1)Nd3TiFe8 cuboctahedra,  an edgeedge with one Fe(1)Nd3TiFe8 cuboctahedra, edges with three equivalent Fe(4)Nd2TiFe9 cuboctahedra, edges with four equivalent Fe(2)Nd3Fe9 cuboctahedra, faces with three equivalent Fe(4)Nd2TiFe9 cuboctahedra, faces with three equivalent Fe(1)Nd3TiFe8 cuboctahedra, and faces with four equivalent Fe(2)Nd3Fe9 cuboctahedra. In the third Fe site, Fe(3) is bonded in a 12-coordinate geometry to one Nd(1), one Nd(2), one Ti(1), one Fe(5), two equivalent Fe(1), two equivalent Fe(2), two equivalent Fe(3), and two equivalent Fe(4) atoms. In the fourth Fe site, Fe(4) is bonded to one Nd(1), one Nd(2), one Ti(1), one Fe(5), two equivalent Fe(1), two equivalent Fe(2), and four equivalent Fe(3) atoms to form distorted FeNd2TiFe9 cuboctahedra that share corners with four equivalent Fe(4)Nd2TiFe9 cuboctahedra, corners with five equivalent Fe(2)Nd3Fe9 cuboctahedra, corners with five equivalent Fe(1)Nd3TiFe8 cuboctahedra, edges with three equivalent Fe(2)Nd3Fe9 cuboctahedra, edges with three equivalent Fe(1)Nd3TiFe8 cuboctahedra, faces with three equivalent Fe(2)Nd3Fe9 cuboctahedra, faces with three equivalent Fe(1)Nd3TiFe8 cuboctahedra, and faces with four equivalent Fe(4)Nd2TiFe9 cuboctahedra. In the fifth Fe site, Fe(5) is bonded in a 1-coordinate geometry to one Nd(1), one Ti(1), three equivalent Fe(2), three equivalent Fe(4), and six equivalent Fe(3) atoms.
Nd2TiFe16 crystallizes in the trigonal R3m space group. There are two inequivalent Nd sites. In the first Nd site, Nd(1) is bonded in a 19-coordinate geometry to one Fe(5), three equivalent Fe(1), three equivalent Fe(4), six equivalent Fe(2), and six equivalent Fe(3) atoms. The Nd(1)-Fe(5) bond length is 3.06 Å. All Nd(1)-Fe(1) bond lengths are 3.11 Å. All Nd(1)-Fe(4) bond lengths are 3.30 Å. There are three shorter (3.22 Å) and three longer (3.25 Å) Nd(1)-Fe(2) bond lengths. All Nd(1)-Fe(3) bond lengths are 3.05 Å. In the second Nd site, Nd(2) is bonded in a 19-coordinate geometry to one Ti(1), three equivalent Fe(2), three equivalent Fe(4), six equivalent Fe(1), and six equivalent Fe(3) atoms. The Nd(2)-Ti(1) bond length is 3.18 Å. All Nd(2)-Fe(2) bond lengths are 3.09 Å. All Nd(2)-Fe(4) bond lengths are 3.36 Å. There are three shorter (3.20 Å) and three longer (3.28 Å) Nd(2)-Fe(1) bond lengths. All Nd(2)-Fe(3) bond lengths are 3.05 Å. Ti(1) is bonded in a 14-coordinate geometry to one Nd(2), one Fe(5), three equivalent Fe(1), three equivalent Fe(4), and six equivalent Fe(3) atoms. The Ti(1)-Fe(5) bond length is 2.39 Å. All Ti(1)-Fe(1) bond lengths are 2.68 Å. All Ti(1)-Fe(4) bond lengths are 2.66 Å. All Ti(1)-Fe(3) bond lengths are 2.77 Å. There are five inequivalent Fe sites. In the first Fe site, Fe(1) is bonded to one Nd(1), two equivalent Nd(2), one Ti(1), two equivalent Fe(2), two equivalent Fe(4), and four equivalent Fe(3) atoms to form FeNd3TiFe8 cuboctahedra that share corners with two equivalent Fe(1)Nd3TiFe8 cuboctahedra, corners with five equivalent Fe(4)Nd2TiFe9 cuboctahedra, corners with eight equivalent Fe(2)Nd3Fe9 cuboctahedra,  an edgeedge with one Fe(2)Nd3Fe9 cuboctahedra, edges with three equivalent Fe(4)Nd2TiFe9 cuboctahedra, edges with four equivalent Fe(1)Nd3TiFe8 cuboctahedra, faces with three equivalent Fe(4)Nd2TiFe9 cuboctahedra, faces with three equivalent Fe(2)Nd3Fe9 cuboctahedra, and faces with four equivalent Fe(1)Nd3TiFe8 cuboctahedra. Both Fe(1)-Fe(2) bond lengths are 2.50 Å. Both Fe(1)-Fe(4) bond lengths are 2.48 Å. There are two shorter (2.55 Å) and two longer (2.66 Å) Fe(1)-Fe(3) bond lengths. In the second Fe site, Fe(2) is bonded to one Nd(2), two equivalent Nd(1), one Fe(5), two equivalent Fe(1), two equivalent Fe(4), and four equivalent Fe(3) atoms to form FeNd3Fe9 cuboctahedra that share corners with two equivalent Fe(2)Nd3Fe9 cuboctahedra, corners with five equivalent Fe(4)Nd2TiFe9 cuboctahedra, corners with eight equivalent Fe(1)Nd3TiFe8 cuboctahedra,  an edgeedge with one Fe(1)Nd3TiFe8 cuboctahedra, edges with three equivalent Fe(4)Nd2TiFe9 cuboctahedra, edges with four equivalent Fe(2)Nd3Fe9 cuboctahedra, faces with three equivalent Fe(4)Nd2TiFe9 cuboctahedra, faces with three equivalent Fe(1)Nd3TiFe8 cuboctahedra, and faces with four equivalent Fe(2)Nd3Fe9 cuboctahedra. The Fe(2)-Fe(5) bond length is 2.63 Å. Both Fe(2)-Fe(4) bond lengths are 2.46 Å. There are two shorter (2.53 Å) and two longer (2.67 Å) Fe(2)-Fe(3) bond lengths. In the third Fe site, Fe(3) is bonded in a 12-coordinate geometry to one Nd(1), one Nd(2), one Ti(1), one Fe(5), two equivalent Fe(1), two equivalent Fe(2), two equivalent Fe(3), and two equivalent Fe(4) atoms. The Fe(3)-Fe(5) bond length is 2.79 Å. There is one shorter (2.51 Å) and one longer (2.52 Å) Fe(3)-Fe(3) bond length. There is one shorter (2.44 Å) and one longer (2.47 Å) Fe(3)-Fe(4) bond length. In the fourth Fe site, Fe(4) is bonded to one Nd(1), one Nd(2), one Ti(1), one Fe(5), two equivalent Fe(1), two equivalent Fe(2), and four equivalent Fe(3) atoms to form distorted FeNd2TiFe9 cuboctahedra that share corners with four equivalent Fe(4)Nd2TiFe9 cuboctahedra, corners with five equivalent Fe(2)Nd3Fe9 cuboctahedra, corners with five equivalent Fe(1)Nd3TiFe8 cuboctahedra, edges with three equivalent Fe(2)Nd3Fe9 cuboctahedra, edges with three equivalent Fe(1)Nd3TiFe8 cuboctahedra, faces with three equivalent Fe(2)Nd3Fe9 cuboctahedra, faces with three equivalent Fe(1)Nd3TiFe8 cuboctahedra, and faces with four equivalent Fe(4)Nd2TiFe9 cuboctahedra. The Fe(4)-Fe(5) bond length is 2.60 Å. In the fifth Fe site, Fe(5) is bonded in a 1-coordinate geometry to one Nd(1), one Ti(1), three equivalent Fe(2), three equivalent Fe(4), and six equivalent Fe(3) atoms.