Cesium dicyanamide Cs[C2N3] (≡ Cs[N(CN)2] or Cs[dca]) was obtained by a metathesis reaction in form of transparent colorless platelets. The results of single-crystal X-ray structure measurements and refinements (C2/c, Z = 8) with the monoclinic cell parameters a = 932.31(8), b = 1274.67(9), c = 824.94(7) pm, β = 110.803(3)° at −70 °C and a = 939.59(7), b = 1281.58(8), c = 827.57(6) pm, β = 110.610(3)° at 20 °C corroborate earlier results for this compound. The Raman and IR spectra of Cs[C2N3] are presented for the first time and the result compares well with those of NaCs2[C2N3]3. The heat-driven cyclotrimerization process of Cs[C2N3] was studied by thermal analyses (DSC) and temperature-dependent X-ray powder diffraction methods. At 370 °C, its trimerization product Cs3[C6N9] is formed, crystallizing in the orthorhombic space group Pbam with the cell parameters a = 3043.0(3), b = 1052.4(1) and c = 415.21(4) pm for Z = 4. The IR spectrum of this cesium tricyanomelaminate (Cs3[C6N9] or Cs3[TCM]) is presented, but a well-resolved Raman spectrum could not be acquired owing to fluorescence phenomena. An overview about the cyclotrimerization reactions of all pseudo-binary alkali-metal dicyanamides (A[C2N3]) to their corresponding tricyanomelaminates (A 3[C6N9]) with A = Li–Cs gives a basis for a discussion of the different thermal and structural characteristics.

中文翻译：

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从 Cs[C2N3] 到 Cs3[C6N9] – 热和结构研究

二氰胺铯 Cs[C2氮3] (= Cs[N(CN))2]或Cs[dca])通过复分解反应获得透明无色片状形式。单晶X射线结构测量和细化的结果（C2/C,Z= 8) 使用单斜晶胞参数A= 932.31(8),乙= 1274.67(9),C= 824.94(7) 下午，β= 110.803(3)° (-70 °C) 且A= 939.59(7),乙= 1281.58(8),C= 827.57(6) 下午,β= 110.610(3)° (20 °C) 证实了该化合物的早期结果。 Cs[C]的拉曼光谱和红外光谱2氮3] 首次提出，结果与 NaCs 的结果相当2[C2氮3]3。 Cs[C]的热驱动环三聚反应过程2氮3] 通过热分析 (DSC) 和温度依赖性 X 射线粉末衍射方法进行了研究。 370℃时，其三聚产物Cs3[C6氮9] 形成，在斜方空间群中结晶巴姆与细胞参数A= 3043.0(3),乙= 1052.4(1) 和C= 415.21(4) pm 为Z= 4. 该三氰基胺酸铯 (Cs3[C6氮9]或铯3[TCM]）已提出，但由于荧光现象而无法获得高分辨率的拉曼光谱。所有准二元碱金属二氰胺的环三聚反应概述（A[C2氮3]) 到其相应的三氰基胺 (A 3[C6氮9]） 和A= Li-Cs 为讨论不同的热和结构特性提供了基础。