Th3Si2 crystallizes in the tetragonal P4/mbm space group. There are two inequivalent Th sites. In the first Th site, Th(1) is bonded in a 3-coordinate geometry to four equivalent Th(2) and three equivalent Si(1) atoms. In the second Th site, Th(2) is bonded in a 10-coordinate geometry to two equivalent Th(2) and eight equivalent Th(1) atoms. Si(1) is bonded in a 4-coordinate geometry to three equivalent Th(1) and one Si(1) atom.
Th3Si2 crystallizes in the tetragonal P4/mbm space group. There are two inequivalent Th sites. In the first Th site, Th(1) is bonded in a 3-coordinate geometry to four equivalent Th(2) and three equivalent Si(1) atoms. All Th(1)-Th(2) bond lengths are 3.78 Å. There is one shorter (2.78 Å) and two longer (2.99 Å) Th(1)-Si(1) bond lengths. In the second Th site, Th(2) is bonded in a 10-coordinate geometry to two equivalent Th(2) and eight equivalent Th(1) atoms. Both Th(2)-Th(2) bond lengths are 3.36 Å. Si(1) is bonded in a 4-coordinate geometry to three equivalent Th(1) and one Si(1) atom. The Si(1)-Si(1) bond length is 2.26 Å.