Ho3TlC is (Cubic) Perovskite structured and crystallizes in the cubic Pm-3m space group. The structure is three-dimensional and consists of one methane molecule and one Ho3Tl framework. In the Ho3Tl framework, Ho is bonded in a linear geometry to two equivalent Tl atoms. Both Ho–Tl bond lengths are 2.79 Å. Tl is bonded to six equivalent Ho atoms to form corner-sharing TlHo6 octahedra. The corner-sharing octahedral tilt angles are 0°.