Cd₂(C₂H₆N₆)₄(NO₃)₄·H₂O (CdHATr), a triazole-based energetic compound, was selected for high-pressure research. Employing in situ Raman scattering and synchrotron angle-dispersive X-ray diffraction (ADXRD) technologies, this study investigated CdHATr up to ∼16.3 GPa at room temperature. The vibrational modes of CdHATr at ambient pressure were comprehensively resolved based on the experimental results. Detailed spectral analyses revealed that CdHATr underwent three pressure-induced phase transitions at 0.5, 2.2, and 5.2 GPa. ADXRD experiments confirmed the presence of these phase transitions, as observed in Raman spectral analyses. By analyzing the changes of the vibrational spectra and the lattice parameters under pressure, it is suggested that the first phase transition arises from the deformation of the 3-hydrazino-4-amino-1,2,4-triazole (HATr) ligand, the second phase transition results from the rearrangement of hydrogen bonds, and the third phase transition is caused by the conformational change of the triazole ring. ADXRD results show that CdHATr may experience an abnormal expansion at 0.5 GPa, which is probably caused by the deformation of the HATr ligand. This work contributes to the understanding of the structures of triazole-based energetic compounds under pressure, which will help in the synthesis of new compounds in the future.

中文翻译：

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高压下Cd2(C2H6N6)4(NO3)·4H2O的拉曼和同步辐射X射线衍射研究


Cd ₂ (C ₂ H ₆ N ₆ ) ₄ (NO ₃ ) ₄ ·H ₂ O (CdHATr)，一种三唑基含能化合物，被选用于高压研究。本研究采用原位拉曼散射和同步加速器角色散 X 射线衍射 (ADXRD) 技术，研究了室温下高达 ∼16.3 GPa 的 CdHATr。根据实验结果全面解析了CdHATr在环境压力下的振动模式。详细的光谱分析表明，CdHATr 在 0.5、2.2 和 5.2 GPa 下经历了三个压力诱导的相变。 ADXRD 实验证实了拉曼光谱分析中观察到的这些相变的存在。通过分析压力下振动光谱和晶格参数的变化，表明第一相变是由3-肼基-4-氨基-1,2,4-三唑（HATr）配体的变形引起的，第二相变是由氢键的重排引起的，第三相变是由三唑环的构象变化引起的。 ADXRD结果表明，CdHATr在0.5 GPa下可能会发生异常膨胀，这可能是由HATr配体的变形引起的。这项工作有助于理解压力下三唑基含能化合物的结构，这将有助于未来新化合物的合成。