A New Allotrope of Nitrogen as High-Energy Density Material

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• 作者：Michael J. Greschner ; Meng Zhang ; Arnab Majumdar ; Hanyu Liu ; Feng Peng ; John S. Tse ; Yansun Yao
• 刊名：Journal of Physical Chemistry A
• 出版年：2016
• 出版时间：May 12, 2016
• 年：2016
• 卷：120
• 期：18
• 页码：2920-2925
• 全文大小：422K
• 年卷期：0
• ISSN：1520-5215

文摘

A new allotrope of nitrogen in which the atoms are connected to form a novel N₆ molecule is predicted to exist at ambient conditions. The N₆ molecule is a charge-transfer complex with an open-chain structure containing both single and triple bonds. The charge transfer induces ionic characteristics in the intermolecular interactions and leads to a much higher cohesive energy for the predicted crystal compared to solid N₂. The N₆ solid is also more stable than a previously reported polymeric solid of nitrogen. Because of the kinetic stability of the molecules and strong intermolecular interactions, the N₆ crystal is shown by metadynamics simulations to be dynamically stable around room temperature and to only dissociate to N₂ molecules above 700 K. The N₆ crystal can likely be synthesized under high-pressure high-temperature conditions, and the considerable metastability may allow for an ambient-pressure recovery of the crystal. Because of the large energy difference between the single and triple bonds, the dissociation of the N₆ crystal is expected to release a large amount of energy, placing it among the most efficient energy materials known today.