Nd2FeCo17Si8 is Bergman Structure: Mg32(Al,Zn)49 Bergman-derived structured and crystallizes in the orthorhombic Fmmm space group. Nd(1) is bonded in a 24-coordinate geometry to four equivalent Co(1), four equivalent Co(2), four equivalent Co(3), four equivalent Co(4), four equivalent Si(1), and four equivalent Si(2) atoms. Fe(1) is bonded to four equivalent Co(2), four equivalent Co(3), and four equivalent Si(1) atoms to form FeCo8Si4 cuboctahedra that share corners with four equivalent Co(4)Nd2Co6Si4 cuboctahedra, faces with four equivalent Co(4)Nd2Co6Si4 cuboctahedra, and faces with four equivalent Co(3)Nd2FeCo5Si4 cuboctahedra. There are five inequivalent Co sites. In the first Co site, Co(1) is bonded in a 11-coordinate geometry to two equivalent Nd(1), one Co(5), two equivalent Co(2), two equivalent Co(4), two equivalent Si(1), and two equivalent Si(2) atoms. In the second Co site, Co(2) is bonded in a 11-coordinate geometry to two equivalent Nd(1), one Fe(1), two equivalent Co(1), two equivalent Co(3), two equivalent Si(1), and two equivalent Si(2) atoms. In the third Co site, Co(3) is bonded to two equivalent Nd(1), one Fe(1), one Co(3), two equivalent Co(2), two equivalent Co(4), two equivalent Si(1), and two equivalent Si(2) atoms to form distorted CoNd2FeCo5Si4 cuboctahedra that share  a cornercorner with one Co(5)Co8Si4 cuboctahedra, corners with five equivalent Co(3)Nd2FeCo5Si4 cuboctahedra, corners with six equivalent Co(4)Nd2Co6Si4 cuboctahedra,  a faceface with one Fe(1)Co8Si4 cuboctahedra,  a faceface with one Co(5)Co8Si4 cuboctahedra, faces with three equivalent Co(3)Nd2FeCo5Si4 cuboctahedra, and faces with four equivalent Co(4)Nd2Co6Si4 cuboctahedra. In the fourth Co site, Co(4) is bonded to two equivalent Nd(1), one Co(4), one Co(5), two equivalent Co(1), two equivalent Co(3), two equivalent Si(1), and two equivalent Si(2) atoms to form distorted CoNd2Co6Si4 cuboctahedra that share  a cornercorner with one Fe(1)Co8Si4 cuboctahedra, corners with five equivalent Co(4)Nd2Co6Si4 cuboctahedra, corners with six equivalent Co(3)Nd2FeCo5Si4 cuboctahedra,  a faceface with one Fe(1)Co8Si4 cuboctahedra,  a faceface with one Co(5)Co8Si4 cuboctahedra, faces with three equivalent Co(4)Nd2Co6Si4 cuboctahedra, and faces with four equivalent Co(3)Nd2FeCo5Si4 cuboctahedra. In the fifth Co site, Co(5) is bonded to four equivalent Co(1), four equivalent Co(4), and four equivalent Si(2) atoms to form CoCo8Si4 cuboctahedra that share corners with four equivalent Co(3)Nd2FeCo5Si4 cuboctahedra, faces with four equivalent Co(4)Nd2Co6Si4 cuboctahedra, and faces with four equivalent Co(3)Nd2FeCo5Si4 cuboctahedra. There are two inequivalent Si sites. In the first Si site, Si(1) is bonded in a 11-coordinate geometry to two equivalent Nd(1), one Fe(1), two equivalent Co(1), two equivalent Co(2), two equivalent Co(3), and two equivalent Co(4) atoms. In the second Si site, Si(2) is bonded in a 12-coordinate geometry to two equivalent Nd(1), one Co(5), two equivalent Co(1), two equivalent Co(2), two equivalent Co(3), two equivalent Co(4), and one Si(2) atom.
Nd2FeCo17Si8 is Bergman Structure: Mg32(Al,Zn)49 Bergman-derived structured and crystallizes in the orthorhombic Fmmm space group. Nd(1) is bonded in a 24-coordinate geometry to four equivalent Co(1), four equivalent Co(2), four equivalent Co(3), four equivalent Co(4), four equivalent Si(1), and four equivalent Si(2) atoms. All Nd(1)-Co(1) bond lengths are 3.15 Å. All Nd(1)-Co(2) bond lengths are 3.15 Å. All Nd(1)-Co(3) bond lengths are 3.32 Å. All Nd(1)-Co(4) bond lengths are 3.31 Å. All Nd(1)-Si(1) bond lengths are 3.23 Å. All Nd(1)-Si(2) bond lengths are 3.24 Å. Fe(1) is bonded to four equivalent Co(2), four equivalent Co(3), and four equivalent Si(1) atoms to form FeCo8Si4 cuboctahedra that share corners with four equivalent Co(4)Nd2Co6Si4 cuboctahedra, faces with four equivalent Co(4)Nd2Co6Si4 cuboctahedra, and faces with four equivalent Co(3)Nd2FeCo5Si4 cuboctahedra. All Fe(1)-Co(2) bond lengths are 2.50 Å. All Fe(1)-Co(3) bond lengths are 2.37 Å. All Fe(1)-Si(1) bond lengths are 2.33 Å. There are five inequivalent Co sites. In the first Co site, Co(1) is bonded in a 11-coordinate geometry to two equivalent Nd(1), one Co(5), two equivalent Co(2), two equivalent Co(4), two equivalent Si(1), and two equivalent Si(2) atoms. The Co(1)-Co(5) bond length is 2.51 Å. Both Co(1)-Co(2) bond lengths are 2.56 Å. Both Co(1)-Co(4) bond lengths are 2.50 Å. There is one shorter (2.31 Å) and one longer (2.32 Å) Co(1)-Si(1) bond length. Both Co(1)-Si(2) bond lengths are 2.43 Å. In the second Co site, Co(2) is bonded in a 11-coordinate geometry to two equivalent Nd(1), one Fe(1), two equivalent Co(1), two equivalent Co(3), two equivalent Si(1), and two equivalent Si(2) atoms. Both Co(2)-Co(3) bond lengths are 2.49 Å. Both Co(2)-Si(1) bond lengths are 2.43 Å. There is one shorter (2.31 Å) and one longer (2.32 Å) Co(2)-Si(2) bond length. In the third Co site, Co(3) is bonded to two equivalent Nd(1), one Fe(1), one Co(3), two equivalent Co(2), two equivalent Co(4), two equivalent Si(1), and two equivalent Si(2) atoms to form distorted CoNd2FeCo5Si4 cuboctahedra that share  a cornercorner with one Co(5)Co8Si4 cuboctahedra, corners with five equivalent Co(3)Nd2FeCo5Si4 cuboctahedra, corners with six equivalent Co(4)Nd2Co6Si4 cuboctahedra,  a faceface with one Fe(1)Co8Si4 cuboctahedra,  a faceface with one Co(5)Co8Si4 cuboctahedra, faces with three equivalent Co(3)Nd2FeCo5Si4 cuboctahedra, and faces with four equivalent Co(4)Nd2Co6Si4 cuboctahedra. The Co(3)-Co(3) bond length is 2.51 Å. Both Co(3)-Co(4) bond lengths are 2.33 Å. Both Co(3)-Si(1) bond lengths are 2.53 Å. Both Co(3)-Si(2) bond lengths are 2.47 Å. In the fourth Co site, Co(4) is bonded to two equivalent Nd(1), one Co(4), one Co(5), two equivalent Co(1), two equivalent Co(3), two equivalent Si(1), and two equivalent Si(2) atoms to form distorted CoNd2Co6Si4 cuboctahedra that share  a cornercorner with one Fe(1)Co8Si4 cuboctahedra, corners with five equivalent Co(4)Nd2Co6Si4 cuboctahedra, corners with six equivalent Co(3)Nd2FeCo5Si4 cuboctahedra,  a faceface with one Fe(1)Co8Si4 cuboctahedra,  a faceface with one Co(5)Co8Si4 cuboctahedra, faces with three equivalent Co(4)Nd2Co6Si4 cuboctahedra, and faces with four equivalent Co(3)Nd2FeCo5Si4 cuboctahedra. The Co(4)-Co(4) bond length is 2.52 Å. The Co(4)-Co(5) bond length is 2.39 Å. Both Co(4)-Si(1) bond lengths are 2.47 Å. Both Co(4)-Si(2) bond lengths are 2.54 Å. In the fifth Co site, Co(5) is bonded to four equivalent Co(1), four equivalent Co(4), and four equivalent Si(2) atoms to form CoCo8Si4 cuboctahedra that share corners with four equivalent Co(3)Nd2FeCo5Si4 cuboctahedra, faces with four equivalent Co(4)Nd2Co6Si4 cuboctahedra, and faces with four equivalent Co(3)Nd2FeCo5Si4 cuboctahedra. All Co(5)-Si(2) bond lengths are 2.32 Å. There are two inequivalent Si sites. In the first Si site, Si(1) is bonded in a 11-coordinate geometry to two equivalent Nd(1), one Fe(1), two equivalent Co(1), two equivalent Co(2), two equivalent Co(3), and two equivalent Co(4) atoms. In the second Si site, Si(2) is bonded in a 12-coordinate geometry to two equivalent Nd(1), one Co(5), two equivalent Co(1), two equivalent Co(2), two equivalent Co(3), two equivalent Co(4), and one Si(2) atom. The Si(2)-Si(2) bond length is 2.80 Å.