Liu Shijie, Zhao Lei, Yao Mingguang, Miao Maosheng, Liu Bingbing
State Key Laboratory of Superhard Materials Jilin University Changchun 130012 China.
School of Physics and Engineering and Henan Key Laboratory of Photoelectric Energy Storage Materials and Applications Henan University of Science and Technology Luoyang 471003 China.
Adv Sci (Weinh). 2020 Mar 30;7(10):1902320. doi: 10.1002/advs.201902320. eCollection 2020 May.
Nitrogen has unique bonding ability to form single, double, and triple bonds, similar to that of carbon. However, a molecular crystal formed by an aromatic polynitrogen similar to a carbon system has not been found yet. Herein, a new form of stable all-nitrogen molecular crystals consisting of only bispentazole N molecules with exceedingly high energy density is predicted. The crystal structures and the conformation of N molecules are strongly correlated, both depending on the applied external pressure. These molecular crystals can be recovered upon the release of the pressure. The first-principles molecular dynamics simulations reveal that these all-nitrogen materials decompose at temperatures much higher than room temperature. The decompositions always start from breaking off N molecules from the nitrogen ring and can release a large amount of energy. These new polynitrogens are aromatic and are more stable than all the other polynitrogen crystals reported previously, providing a new green strategy to get all-nitrogen, nonpolluting high energy density materials without introducing any metal or other guest stabilizer.
氮具有与碳类似的形成单键、双键和三键的独特键合能力。然而，尚未发现由类似于碳体系的芳香族多氮形成的分子晶体。在此，预测了一种仅由具有极高能量密度的双戊唑N分子组成的新型稳定全氮分子晶体。N分子的晶体结构和构象密切相关，二者均取决于所施加的外部压力。释放压力后，这些分子晶体可以恢复。第一性原理分子动力学模拟表明，这些全氮材料在远高于室温的温度下分解。分解总是从氮环上断开N分子开始，并能释放大量能量。这些新型多氮化合物具有芳香性，并且比先前报道的所有其他多氮晶体更稳定，为获得不含任何金属或其他客体稳定剂的全氮、无污染高能量密度材料提供了一种新的绿色策略。
