The structural motifs of SiO₂ or silicates, on one hand, and their heavier homologues of group 14 (T) and group 16 (E) elements, on the other hand, commonly differ, as the strict adherence to corner‐sharing is not necessary in the latter owing to larger interatomic distances. On the contrary: larger coordination numbers as well as edge‐sharing of the coordination polyhedra are preferred in [T_xE_y] subunits with T = Si, Ge, Sn and E = S, Se, Te. Hence, we were surprised to find a new modification of the selenido stannate K₂Sn₂Se₅, which is comprised of exclusively corner‐sharing [SnSe₄] tetrahedra in a layer‐type anionic substructure 2D‐{[Sn₂Se₅]^2–}. While the structure of the title compound 2D‐K₂Sn₂Se₅ (1) differs significantly from the known parent compound, 3D‐K₂Se₂Se₅, it shows similarities with layered silicates of the apophyllite family. To the best of our knowledge, 1 represents the first known selenido stannate with an oxo silicate‐like 2D structure. It formed besides known selenido stannes upon heating 3D‐K₂Sn₂Se₅ in in imidazolium‐based ionic liquids (C₂C₂Im)[BF₄] or (C₂C₂Im)[BF₄] in the presence of DMMP and Cd²⁺ or Zn²⁺.

中文翻译：

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离子液体中硒酸亚锡酸盐的尺寸还原形成2D-K2Sn2Se5，这是含氧硅酸盐的直接重合物

一方面，SiO ₂或硅酸盐的结构基序，另一方面，它们在第14（T）和第16（E）组元素的较重同系物上通常有所不同，因为不需要严格遵守转角共享在后者中是由于较大的原子间距离。相反，在[T _x E _y ]亚基中，T = Si，Ge，Sn和E = S，Se，Te的情况下，优选较大的配位数以及配位多面体的边共享。因此，我们惊讶地发现了硒酸锡酸钾K ₂ Sn ₂ Se _{5的新变体}，该变体仅由角共享的[SnSe ₄ ]四面体构成，层状阴离子亚结构2D-{[Sn ₂Se ₅ ] ^2– }。尽管标题化合物2D-K ₂ Sn ₂ Se ₅（1）的结构与已知的母体化合物3D-K ₂ Se ₂ Se ₅（1）显着不同，但它显示了与载脂沸石家族的层状硅酸盐相似。据我们所知，1代表第一个已知的具有类似硅酸羰基2D结构的硒酸亚硒酸盐。它在咪唑基离子液体（C ₂ C ₂ Im）[BF _4]中加热3D-K ₂ Sn ₂ Se ₅时与已知的硒基锡一起形成。]或（C ₂ C ₂ Im）[BF ₄ ]在DMMP和Cd ²⁺或Zn ²⁺的存在下。