Pressure- and Temperature-Dependent Structural Stability of LLM-105 Crystal
Pressure- and Temperature-Dependent Structural Stability of LLM-105 Crystal
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LLM-105 晶体的压力和温度依赖性结构稳定性
DOI：
10.1021/acs.jpcc.8b10837
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发表时间：
2019-01-17
影响因子：
3.7
通讯作者：
Zhang, Zengming
中科院分区：
文献类型：
--
作者：
Xu, Zilong;Su, Hao;Zhang, Zengming
根据高压或低温X射线衍射图谱，新含能材料2，6-二氨基-3，5-二硝基吡嗪-1-氧化物（C_4H_4N_6O_5，LLM-105）在室温下30 GPa以下的高压或常压下513 ~ 5 K的温度范围内保持其结构稳定性。一个结构相变发生在约30 GPa，并证实了压力相关的拉曼和红外光谱。LLM-105晶体的结构在压力下表现出顺序为β（B）> β（a）> β（c）的各向异性压缩性和顺序为α（B）> α（c）的各向异性热膨胀性，其近似于α（a）。基于在不同压力或温度下的晶格参数，获得该晶体的德拜温度为1225 K。实验数据表明，与冷却相比，压缩是减小LLM-105晶体体积的更好方法。在极端条件下的拉曼和红外光谱表明，LLM-105晶体内较强的分子间和分子内氢键网络有助于结构稳定性。将氨基的对称和非对称伸缩模耦合起来，可以提高对LLM-105晶体压力演化的理解。得到了不同压力和温度下氨基的键常数。
The new energetic material 2,6-diamino-3,5-dinitropyrazine-1-oxide (C4H4N6O5, LLM-105) maintains its structural stability under high pressure below 30 GPa at room temperature or in the temperature range from 513 to 5 K with ambient pressure based on the high pressure or the cryogenic X-ray diffraction patterns. One structural phase transition occurs at about 30 GPa and is confirmed by the pressure-dependent Raman and infrared spectra. The structure of the LLM-105 crystal shows anisotropic compressibility under pressure in the order beta(b) > beta(a) > beta(c) and anisotropic thermal expansion in the order alpha(b) > alpha(c) approximate to alpha(a) A Debye temperature of 1225 K is obtained for this crystal based on the lattice parameters at different pressures or temperatures. The experimental data reveal that compression is a better method to reduce the volume of the LLM-105 crystal compared with cooling. Raman and infrared spectra at extreme conditions suggest that the structural stability is contributed to the stronger inter- and intramolecular hydrogen-bonding networks within the LLM-105 crystal. The symmetric and asymmetric stretching modes of amino groups are coupled and it can improve the understanding of pressure evolution of the LLM-105 crystal. The bond constants of amino groups with different pressures and temperatures are also obtained.