Zhang Guozhao, Zhang Haiwa, Ninet Sandra, Zhu Hongyang, Beneut Keevin, Liu Cailong, Mezouar Mohamed, Gao Chunxiao, Datchi Frédéric
State Key Laboratory of Superhard Materials, Jilin University, Changchun 130012, China.
Institut de Minéralogie, de Physique des Matériaux et de Cosmochimie (IMPMC), Sorbonne Université, CNRS UMR 7590, MNHN, 4 Place Jussieu, F-75005 Paris, France.
Materials (Basel). 2020 Sep 15;13(18):4102. doi: 10.3390/ma13184102.
The compression of ammonium azide (AA) has been considered to be a promising route for producing high energy-density polynitrogen compounds. So far though, there is no experimental evidence that pure AA can be transformed into polynitrogen materials under high pressure at room temperature. We report here on high pressure () and temperature () experiments on AA embedded in N2 and on pure AA in the range 0-30 GPa, 300-700 K. The decomposition of AA into N2 and NH3 was observed in liquid N2 around 15 GPa-700 K. For pressures above 20 GPa, our results show that AA in N2 transforms into a new crystalline compound and solid ammonia when heated above 620 K. This compound is stable at room temperature and on decompression down to at least 7.0 GPa. Pure AA also transforms into a new compound at similar - conditions, but the product is different. The newly observed phases are studied by Raman spectroscopy and X-ray diffraction and compared to nitrogen and hydronitrogen compounds that have been predicted in the literature. While there is no exact match with any of them, similar vibrational features are found between the product that was obtained in AA + N2 with a polymeric compound of N9H formula.
叠氮化铵（AA）的压缩被认为是制备高能量密度多氮化合物的一条有前景的途径。然而，到目前为止，尚无实验证据表明纯AA在室温高压下可转化为多氮材料。我们在此报告了对嵌入N₂中的AA以及0 - 30 GPa、300 - 700 K范围内的纯AA进行的高压（）和温度（）实验。在15 GPa - 700 K左右的液氮中观察到AA分解为N₂和NH₃。对于高于20 GPa的压力，我们的结果表明，N₂中的AA在加热到620 K以上时会转变为一种新的晶体化合物和固态氨。该化合物在室温下以及减压至至少7.0 GPa时都很稳定。纯AA在类似的 - 条件下也会转变为一种新化合物，但产物不同。通过拉曼光谱和X射线衍射对新观察到的相进行了研究，并与文献中预测的氮和氢氮化合物进行了比较。虽然与它们中的任何一个都不完全匹配，但在AA + N₂中获得的产物与N₉H分子式的聚合物化合物之间发现了相似的振动特征。
