Isothermal sections of the Tl₂Se–CdSe–Ge(Sn)Se₂ systems at 570 ​K were investigated by X-ray powder diffraction (XRPD), scanning electron microscopy (SEM) and energy dispersive X-ray spectroscopy (EDS). The existence of the Tl₂CdSnSe₄ compound was confirmed, and the formation of the Tl₂CdGe₃Se₈, Tl₂CdGeSe₄, Tl₂CdSiTe₄, Tl₂HgSiTe₄ compounds was established. The four equimolar isostructural compounds crystallize in the tetragonal SG I-42m (Pearson symbol tI16) which is a superstructure to the Tl⁺¹[Tl⁺³Se₂]⁻¹ structural type (SG I4/mcm). The lattice parameters of the quaternary compounds are a ​= ​0.80145(9), c ​= ​0.67234(9) nm (Tl₂CdGeSe₄); a ​= ​0.84121(6), c ​= ​0.70289(9) nm (Tl₂CdSiTe₄); a ​= 0.83929(4), c ​= ​0.70396(5) nm (Tl₂HgSiTe₄). The optical bandgap is 1.71 and 1.39 ​eV for Tl₂CdGeSe₄ and Tl₂CdSnSe₄, respectively.

通过X射线粉末衍射（XRPD），扫描电子显微镜（SEM）和能量色散X射线光谱（EDS）研究了570 K下Tl ₂ Se–CdSe–Ge（Sn）Se ₂系统的等温截面。确认存在Tl ₂ CdSnSe ₄化合物，并确定了Tl ₂ CdGe ₃ Se ₈，Tl ₂ CdGeSe ₄，Tl ₂ CdSiTe ₄，Tl ₂ HgSiTe ₄化合物的形成。四种等摩尔的同构化合物在四方SG I -42 m（Pearson符号）中结晶tI 16）是Tl ⁺¹ [Tl ⁺³ Se ₂ ] ^-1结构类型（SG I 4 / mcm）的上层结构。四元化合物的晶格参数为a  = 0.80145（9），c  = 0.67234（9）nm（Tl ₂ CdGeSe ₄）; a  = 0.84121（6），c  = 0.70289（9）nm（Tl ₂ CdSiTe ₄）; a = 0.83929（4），c  = 0.70396（5）nm（Tl ₂ HgSiTe ₄）。Tl ₂的光学带隙为1.71和1.39 eVCdGeSe ₄和Tl ₂ CdSnSe ₄。