TlFeSe2 crystallizes in the tetragonal I-4m2 space group. Fe(1) is bonded to four equivalent Se(1) atoms to form corner-sharing FeSe4 tetrahedra. Tl(1) is bonded in a distorted body-centered cubic geometry to eight equivalent Se(1) atoms. Se(1) is bonded in a water-like geometry to two equivalent Fe(1) and four equivalent Tl(1) atoms.
TlFeSe2 crystallizes in the tetragonal I-4m2 space group. Fe(1) is bonded to four equivalent Se(1) atoms to form corner-sharing FeSe4 tetrahedra. All Fe(1)-Se(1) bond lengths are 2.38 Å. Tl(1) is bonded in a distorted body-centered cubic geometry to eight equivalent Se(1) atoms. All Tl(1)-Se(1) bond lengths are 3.40 Å. Se(1) is bonded in a water-like geometry to two equivalent Fe(1) and four equivalent Tl(1) atoms.