Ti5Si4 crystallizes in the tetragonal P4_12_12 space group. There are three inequivalent Ti sites. In the first Ti site, Ti(1) is bonded in a 6-coordinate geometry to three equivalent Si(1) and three equivalent Si(2) atoms. In the second Ti site, Ti(2) is bonded in a 7-coordinate geometry to three equivalent Si(1) and four equivalent Si(2) atoms. In the third Ti site, Ti(3) is bonded to two equivalent Si(2) and four equivalent Si(1) atoms to form distorted corner-sharing TiSi6 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 Ti(3), three equivalent Ti(1), three equivalent Ti(2), and one Si(2) atom. In the second Si site, Si(2) is bonded in a 9-coordinate geometry to one Ti(3), three equivalent Ti(1), four equivalent Ti(2), and one Si(1) atom.
Ti5Si4 crystallizes in the tetragonal P4_12_12 space group. There are three inequivalent Ti sites. In the first Ti site, Ti(1) is bonded in a 6-coordinate geometry to three equivalent Si(1) and three equivalent Si(2) atoms. There are a spread of Ti(1)-Si(1) bond distances ranging from 2.50-2.56 Å. There are a spread of Ti(1)-Si(2) bond distances ranging from 2.46-2.62 Å. In the second Ti site, Ti(2) is bonded in a 7-coordinate geometry to three equivalent Si(1) and four equivalent Si(2) atoms. There are a spread of Ti(2)-Si(1) bond distances ranging from 2.65-2.85 Å. There are a spread of Ti(2)-Si(2) bond distances ranging from 2.59-2.86 Å. In the third Ti site, Ti(3) is bonded to two equivalent Si(2) and four equivalent Si(1) atoms to form distorted corner-sharing TiSi6 octahedra. The corner-sharing octahedral tilt angles are 54°. Both Ti(3)-Si(2) bond lengths are 2.70 Å. There are two shorter (2.57 Å) and two longer (2.62 Å) Ti(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 Ti(3), three equivalent Ti(1), three equivalent Ti(2), and one Si(2) atom. The Si(1)-Si(2) bond length is 2.41 Å. In the second Si site, Si(2) is bonded in a 9-coordinate geometry to one Ti(3), three equivalent Ti(1), four equivalent Ti(2), and one Si(1) atom.