New functional materials of As-based multinary chalcogenidometalates have received special attention due to their different oxidation states and flexible building blocks. In this work, two new quaternary thioarsenates(III), namely Cs₂Ag₂As₂S₅ (I) and Cs₃AgAs₄S₈ (II), have been obtained by a simple surfactant–thermal technique. Their structures were determined on the basis of single-crystal X-ray diffraction; compound I belongs to the triclinic space group P (no. 2) [a = 7.49(2) Å, b = 9.30(2) Å, c = 9.94(2) Å, α = 63.28(3)°, β = 82.11(3)°, γ = 87.78(3)°, V = 612.4(2) ų and Z = 2], whereas compound II crystallizes in the monoclinic space group C2/c (no. 12) [a = 27.76(6) Å, b = 6.98(2) Å, c = 19.68(4) Å, β = 109.85(3)°, V = 3586.7(2) ų and Z = 8]. Both structures are shown to feature two-dimensional (2D) layers with different arrangements of Ag–S and As–S asymmetric building units (ABUs). In compound I, the layer is constructed from vertex-sharing dimeric [As₂S₅] units linked by tetrameric [Ag₄S₈] moieties. The layered structure in compound II is formed by 2₁ helical chains based on [As₄S₉] groups which are further interconnected by tetrahedral [AgS₄] chains. The analysis of the quaternary X–Ag–As–S (X = cations) system shows that various combination ways of Ag–S and As–S ABUs in these sulfides can be attributed to the cation-cation repulsion and stereochemically active lone-pair effect. The UV-vis/NIR absorption spectrum indicates that the optical band energy (E_g) of compounds I and II is 2.48 eV and 2.24 eV, respectively. Moreover, theoretical calculations indicate that the As–S and Ag–S bonding states determine the optical properties of the title compounds. This work not only enriches the structural chemistry of thioarsenates, but also opens up a new avenue for exploring novel multinary chalcogenidometalates.

中文翻译：

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四元Cs-Ag-As-S家族的两个新成员，具有不同的Ag-S和As-S不对称建筑单元排列：合成，结构和理论研究。

As基多元硫属金属化物的新型功能材料由于其不同的氧化态和灵活的结构单元而受到了特别的关注。在这项工作中，两个新的季thioarsenates（III），即铯₂的Ag ₂作为₂小号₅（我）和Cs _3个AGAS ₄ š ₈（II），已经通过一个简单的表面活性剂的热技术获得。它们的结构是根据单晶X射线衍射确定的。化合物I属于三斜空间群P（编号2）[ a = 7.49（2）Å，b= 9.30（2）埃，c ^ = 9.94（2）埃，α = 63.28（3）°，β = 82.11（3）°，γ = 87.78（3）°，V = 612.4（2）埃³和ž = 2]，而化合物II在单斜空间群C 2 / c（第12号）中结晶[ a = 27.76（6）Å，b = 6.98（2）Å，c = 19.68（4）Å，β = 109.85（ 3）°，V = 3586.7（2）埃³和ž= 8]。两种结构均显示为二维（2D）层，具有不同的Ag–S和As–S非对称建筑单元（ABU）排列。在化合物I中，该层由通过四聚体[Ag ₄ S ₈ ]部分连接的共享顶点的二聚体[As ₂ S ₅ ]单元构成。化合物II中的层状结构由基于[As ₄ S ₉ ]基的2 ₁螺旋链形成，这些螺旋链进一步通过四面体[AgS ₄ ]相互连接]链。对四元X–Ag–As–S（X =阳离子）系统的分析表明，这些硫化物中Ag–S和As–S ABU的各种组合方式可归因于阳离子排斥和立体化学活性孤对影响。UV-vis / NIR吸收光谱表明，化合物I和II的光带能量（E _g）分别为2.48 eV和2.24 eV。此外，理论计算表明，As-S和Ag-S的键合状态决定了标题化合物的光学性质。这项工作不仅丰富了硫代砷酸盐的结构化学，而且还为探索新型多元硫属元素金属化物开辟了一条新途径。