Wei Shuli, Li Da, Liu Zhao, Li Xin, Tian Fubo, Duan Defang, Liu Bingbing, Cui Tian
State Key Laboratory of Superhard Materials, College of Physics, Jilin University, Changchun, 130012, People's Republic of China.
Phys Chem Chem Phys. 2017 Mar 29;19(13):9246-9252. doi: 10.1039/c6cp08771j.
The high-pressure structural evolutionary behaviors of magnesium polynitrides were studied up to 100 GPa using first-principles calculations. Using the unbiased structure searching method, five stable chemical stoichiometries of magnesium polynitrides (MgN, MgN, MgN, MgN, and MgN) were theoretically predicted at high pressures. The predicted MgN compounds contain a rich variety of polynitrogen forms ranging from charged molecules (one-dimensional bent molecules N, planar triangle N to benzene-like rings N) to extended polymeric chains (N). To the best of our knowledge, this is the first time that stable bent molecules N, planar triangle N, and polymeric chains (N) were predicted in alkaline-earth metal polynitrides. The decomposition of P1[combining macron]-MgN and P1[combining macron]-MgN are expected to be highly exothermic, releasing an energy of approximately 2.83 kJ g and 2.01 kJ g, respectively. Furthermore, P1[combining macron]-MgN can be synthesized at several GPa. The results of the present study suggest that it is possible to obtain energetic polynitrogen in main-group nitrides under high pressure.
利用第一性原理计算研究了多氮化镁在高达100吉帕压力下的高压结构演化行为。采用无偏结构搜索方法，从理论上预测了多氮化镁的五种稳定化学计量比（MgN、MgN、MgN、MgN和MgN）。预测的MgN化合物包含多种多氮形式，从带电分子（一维弯曲分子N、平面三角形N到苯环状N）到扩展的聚合物链（N）。据我们所知，这是首次在碱土金属多氮化物中预测到稳定的弯曲分子N、平面三角形N和聚合物链（N）。预计P1[组合 Macron]-MgN和P1[组合 Macron]-MgN的分解将是高度放热的，分别释放约2.83千焦/克和2.01千焦/克的能量。此外，P1[组合 Macron]-MgN可以在几个吉帕的压力下合成。本研究结果表明，在高压下有可能在主族氮化物中获得含能多氮化物。
