Zr5Si4 crystallizes in the tetragonal P4_12_12 space group. There are three inequivalent Zr sites. In the first Zr site, Zr(1) is bonded in a 6-coordinate geometry to three equivalent Si(1) and three equivalent Si(2) atoms. In the second Zr site, Zr(2) is bonded in a 7-coordinate geometry to three equivalent Si(1) and four equivalent Si(2) atoms. In the third Zr site, Zr(3) is bonded to two equivalent Si(2) and four equivalent Si(1) atoms to form corner-sharing ZrSi6 octahedra. The corner-sharing octahedral tilt angles are 54°. There are two inequivalent Si sites. In the first Si site, Si(1) is bonded in a 9-coordinate geometry to two equivalent Zr(3), three equivalent Zr(1), three equivalent Zr(2), and one Si(2) atom. In the second Si site, Si(2) is bonded in a 9-coordinate geometry to one Zr(3), three equivalent Zr(1), four equivalent Zr(2), and one Si(1) atom.
Zr5Si4 crystallizes in the tetragonal P4_12_12 space group. There are three inequivalent Zr sites. In the first Zr site, Zr(1) is bonded in a 6-coordinate geometry to three equivalent Si(1) and three equivalent Si(2) atoms. There are a spread of Zr(1)-Si(1) bond distances ranging from 2.69-2.72 Å. There are a spread of Zr(1)-Si(2) bond distances ranging from 2.64-2.79 Å. In the second Zr site, Zr(2) is bonded in a 7-coordinate geometry to three equivalent Si(1) and four equivalent Si(2) atoms. There are a spread of Zr(2)-Si(1) bond distances ranging from 2.82-3.05 Å. There are a spread of Zr(2)-Si(2) bond distances ranging from 2.77-3.15 Å. In the third Zr site, Zr(3) is bonded to two equivalent Si(2) and four equivalent Si(1) atoms to form corner-sharing ZrSi6 octahedra. The corner-sharing octahedral tilt angles are 54°. Both Zr(3)-Si(2) bond lengths are 2.89 Å. There are two shorter (2.76 Å) and two longer (2.81 Å) Zr(3)-Si(1) bond lengths. There are two inequivalent Si sites. In the first Si site, Si(1) is bonded in a 9-coordinate geometry to two equivalent Zr(3), three equivalent Zr(1), three equivalent Zr(2), and one Si(2) atom. The Si(1)-Si(2) bond length is 2.49 Å. In the second Si site, Si(2) is bonded in a 9-coordinate geometry to one Zr(3), three equivalent Zr(1), four equivalent Zr(2), and one Si(1) atom.