(TaSe4)2I crystallizes in the tetragonal I422 space group. There are two inequivalent Ta sites. In the first Ta site, Ta(1) is bonded in a 8-coordinate geometry to four equivalent Se(1) and four equivalent Se(2) atoms. In the second Ta site, Ta(2) is bonded in a 8-coordinate geometry to four equivalent Se(1) and four equivalent Se(2) atoms. There are two inequivalent Se sites. In the first Se site, Se(1) is bonded in a 3-coordinate geometry to one Ta(1), one Ta(2), and one Se(2) atom. In the second Se site, Se(2) is bonded in a 2-coordinate geometry to one Ta(1), one Ta(2), one Se(1), and one I(1) atom. I(1) is bonded in a distorted square co-planar geometry to four equivalent Se(2) atoms.
(TaSe4)2I crystallizes in the tetragonal I422 space group. There are two inequivalent Ta sites. In the first Ta site, Ta(1) is bonded in a 8-coordinate geometry to four equivalent Se(1) and four equivalent Se(2) atoms. All Ta(1)-Se(1) bond lengths are 2.62 Å. All Ta(1)-Se(2) bond lengths are 2.73 Å. In the second Ta site, Ta(2) is bonded in a 8-coordinate geometry to four equivalent Se(1) and four equivalent Se(2) atoms. All Ta(2)-Se(1) bond lengths are 2.70 Å. All Ta(2)-Se(2) bond lengths are 2.65 Å. There are two inequivalent Se sites. In the first Se site, Se(1) is bonded in a 3-coordinate geometry to one Ta(1), one Ta(2), and one Se(2) atom. The Se(1)-Se(2) bond length is 2.43 Å. In the second Se site, Se(2) is bonded in a 2-coordinate geometry to one Ta(1), one Ta(2), one Se(1), and one I(1) atom. The Se(2)-I(1) bond length is 3.33 Å. I(1) is bonded in a distorted square co-planar geometry to four equivalent Se(2) atoms.