NdFeSi2 crystallizes in the orthorhombic Cmcm space group. Nd(1) is bonded in a 14-coordinate geometry to four equivalent Fe(1), four equivalent Si(1), and six equivalent Si(2) atoms. Fe(1) is bonded in a 4-coordinate geometry to four equivalent Nd(1) and four equivalent Si(1) atoms. There are two inequivalent Si sites. In the first Si site, Si(1) is bonded in a 4-coordinate geometry to four equivalent Nd(1), four equivalent Fe(1), and one Si(2) atom. In the second Si site, Si(2) is bonded in a 9-coordinate geometry to six equivalent Nd(1), one Si(1), and two equivalent Si(2) atoms.
NdFeSi2 crystallizes in the orthorhombic Cmcm space group. Nd(1) is bonded in a 14-coordinate geometry to four equivalent Fe(1), four equivalent Si(1), and six equivalent Si(2) atoms. There are two shorter (3.13 Å) and two longer (3.14 Å) Nd(1)-Fe(1) bond lengths. All Nd(1)-Si(1) bond lengths are 3.18 Å. There are four shorter (3.10 Å) and two longer (3.20 Å) Nd(1)-Si(2) bond lengths. Fe(1) is bonded in a 4-coordinate geometry to four equivalent Nd(1) and four equivalent Si(1) atoms. There are two shorter (2.24 Å) and two longer (2.29 Å) Fe(1)-Si(1) bond lengths. There are two inequivalent Si sites. In the first Si site, Si(1) is bonded in a 4-coordinate geometry to four equivalent Nd(1), four equivalent Fe(1), and one Si(2) atom. The Si(1)-Si(2) bond length is 2.56 Å. In the second Si site, Si(2) is bonded in a 9-coordinate geometry to six equivalent Nd(1), one Si(1), and two equivalent Si(2) atoms. Both Si(2)-Si(2) bond lengths are 2.37 Å.