Th2Tl is Khatyrkite structured and crystallizes in the tetragonal I4/mcm space group. The structure is three-dimensional. Th is bonded in a 4-coordinate geometry to four equivalent Tl atoms. All Th–Tl bond lengths are 3.36 Å. Tl is bonded in a 10-coordinate geometry to eight equivalent Th and two equivalent Tl atoms. Both Tl–Tl bond lengths are 3.03 Å.