We report two new quaternary BaCu₆Sn₂As_4−x and BaCu₆Sn₂P_4−x phases with a new structure type, which are fully characterized by single crystal X-ray diffraction, scanning electron microscopy (SEM), transmission electron microscopy (TEM) and scanning transmission electron microscopy (STEM). These two phases crystallize in tetragonal cell with space group I4/mmm (#139) and Pearson symbol tI26. The refined lattice parameters are a = 4.164(1) Å, c = 24.088(3) Å for BaCu₆Sn₂As_4−x, and a = 4.053(2) Å, c = 24.08(1) Å for BaCu₆Sn₂P_4−x, respectively. They possess a distinct layered feature composed of Cu₆Sn₂Pn_x (Pn = P, As) layers sandwiched by the Ba atoms. The Cu-Sn framework of the Cu₆Sn₂Pn_x layer is closely related to the well-known Cu₂Sb-type structure, and Pn atoms are found occupying two interstitial sites caused by close packing of Cu and Sn atoms or capped on the top of square nets formed by Cu atoms. The compounds are also characterized by electrical transport measurements down to 2 K.

我们报告了两种具有新结构类型的新四元 BaCu ₆ Sn ₂ As _4-x和 BaCu ₆ Sn ₂ P _4-x相，它们通过单晶 X 射线衍射、扫描电子显微镜 (SEM)、透射电子显微镜 (TEM) 和扫描透射电子显微镜 (STEM)。这两个相在空间群为I4/mmm (#139) 和 Pearson 符号 tI26 的四方晶胞中结晶。BaCu ₆ Sn ₂ As _4−x的精制晶格参数为a = 4.164(1) Å，c = 24.088(3) Å ，a = 4.053(2) Å，对于 BaCu ₆ Sn ₂ P _4-x，c = 24.08(1) Å ，分别。它们具有明显的分层特征，由被 Ba 原子夹在中间的 Cu ₆ Sn ₂ Pn _x (Pn = P, As) 层组成。Cu ₆ Sn ₂ Pn _x层的 Cu-Sn 骨架与众所周知的 Cu ₂ Sb 型结构密切相关，并且发现 Pn 原子占据了由 Cu 和 Sn 原子紧密堆积引起的两个间隙位置或被覆盖在由铜原子形成的方形网的顶部。这些化合物的特征还在于低至 2 K 的电传输测量。