Nd2FeCo3Si4 crystallizes in the tetragonal P-4m2 space group. Nd(1) is bonded in a 16-coordinate geometry to two equivalent Fe(1), two equivalent Co(1), two equivalent Co(2), two equivalent Co(3), four equivalent Si(1), and four equivalent Si(2) atoms. Fe(1) is bonded in a 4-coordinate geometry to four equivalent Nd(1), four equivalent Co(2), and four equivalent Si(1) atoms. There are three inequivalent Co sites. In the first Co site, Co(1) is bonded in a 4-coordinate geometry to four equivalent Nd(1) and four equivalent Si(2) atoms. In the second Co site, Co(2) is bonded to four equivalent Nd(1), four equivalent Fe(1), and four equivalent Si(1) atoms to form a mixture of distorted face and corner-sharing CoNd4Fe4Si4 cuboctahedra. In the third Co site, Co(3) is bonded in a 4-coordinate geometry to four equivalent Nd(1) and four equivalent Si(2) atoms. There are two inequivalent Si sites. In the first Si site, Si(1) is bonded in a 9-coordinate geometry to four equivalent Nd(1), two equivalent Fe(1), two equivalent Co(2), and one Si(2) atom. In the second Si site, Si(2) is bonded in a 9-coordinate geometry to four equivalent Nd(1), two equivalent Co(1), two equivalent Co(3), and one Si(1) atom.
Nd2FeCo3Si4 crystallizes in the tetragonal P-4m2 space group. Nd(1) is bonded in a 16-coordinate geometry to two equivalent Fe(1), two equivalent Co(1), two equivalent Co(2), two equivalent Co(3), four equivalent Si(1), and four equivalent Si(2) atoms. Both Nd(1)-Fe(1) bond lengths are 3.17 Å. Both Nd(1)-Co(1) bond lengths are 3.20 Å. Both Nd(1)-Co(2) bond lengths are 3.17 Å. Both Nd(1)-Co(3) bond lengths are 3.20 Å. All Nd(1)-Si(1) bond lengths are 3.11 Å. All Nd(1)-Si(2) bond lengths are 3.11 Å. Fe(1) is bonded in a 4-coordinate geometry to four equivalent Nd(1), four equivalent Co(2), and four equivalent Si(1) atoms. All Fe(1)-Co(2) bond lengths are 2.80 Å. All Fe(1)-Si(1) bond lengths are 2.28 Å. There are three inequivalent Co sites. In the first Co site, Co(1) is bonded in a 4-coordinate geometry to four equivalent Nd(1) and four equivalent Si(2) atoms. All Co(1)-Si(2) bond lengths are 2.30 Å. In the second Co site, Co(2) is bonded to four equivalent Nd(1), four equivalent Fe(1), and four equivalent Si(1) atoms to form a mixture of distorted face and corner-sharing CoNd4Fe4Si4 cuboctahedra. All Co(2)-Si(1) bond lengths are 2.28 Å. In the third Co site, Co(3) is bonded in a 4-coordinate geometry to four equivalent Nd(1) and four equivalent Si(2) atoms. All Co(3)-Si(2) bond lengths are 2.30 Å. There are two inequivalent Si sites. In the first Si site, Si(1) is bonded in a 9-coordinate geometry to four equivalent Nd(1), two equivalent Fe(1), two equivalent Co(2), and one Si(2) atom. The Si(1)-Si(2) bond length is 2.69 Å. In the second Si site, Si(2) is bonded in a 9-coordinate geometry to four equivalent Nd(1), two equivalent Co(1), two equivalent Co(3), and one Si(1) atom.