The asymmetric unit of (I) consists of each six symmetry-independent thallium positions and alkali metal positions, while in (II) there are nine symmetry-independent thallium and alkali metal positions, which are all located on a general Wyckoff position 8f. The compressed octahedra in the two new compounds are similar to those in CsTl 10 , in the solid solution K1-xRbxTl, Cs7.29K5.71Tl13 , A10Tl6O2(A=K, Rb) , Cs10Tl6TtO4 (Tt=Si, Ge) and Cs10Tl6SnO3 47 (see table distances and distortion degree in SI chapter 5).