State Key Laboratory of Superhard Materials, College of Physics, Jilin University, Changchun 130012, P. R. China.
Dalton Trans. 2023 Jan 24;52(4):1000-1008. doi: 10.1039/d2dt03394a.
Five new high-pressure phases (4̄3-YN, 3-YN, 1̄-II-YN, 1̄-YN, and 31-YN) are proposed by the crystal structure prediction. A series of polynitrogen forms were achieved in the nitrogen-rich Y-N compounds, including diatomic N, an isolated N chain, an infinite N chain with an N unit, and an infinite N layer with bent N rings. The high energy densities of 1̄-II-YN (1.98 kJ g), 1̄-YN (2.35 kJ g), and 31-YN (3.77 kJ g) make them potential high energy density materials. More importantly, 1̄-II-YN, 1̄-YN, and 31-YN exhibit excellent explosive performance, with detonation pressures 4-8 times that of TNT (19 GPa) and detonation velocities 1-2 times that of TNT (6.90 km s). The electronic structure and bonding properties show that the high stability of Y-N compounds originates from the strong N-N covalent bond and the weak Y-N ionic bond interaction. The increase in the transferred charge quantity as the pressure decreased is more conducive to stabilizing the polymeric nitrogen structure, which leads to the metastable properties of 1̄-II-YN and 1̄-YN under ambient conditions. Finally, the infrared (IR) spectra of 1̄-II-YN, 1̄-YN, and 31-YN are calculated to provide a reference in experimental synthesis.
五种新的高压相（4̄3-YN、3-YN、1̄-II-YN、1̄-YN 和 31-YN）通过晶体结构预测提出。在富氮 Y-N 化合物中实现了一系列多氮形式，包括双原子 N、孤立的 N 链、具有 N 单元的无限 N 链和具有弯曲 N 环的无限 N 层。1̄-II-YN（1.98 kJ g）、1̄-YN（2.35 kJ g）和 31-YN（3.77 kJ g）的高能量密度使它们成为潜在的高能量密度材料。更重要的是，1̄-II-YN、1̄-YN 和 31-YN 表现出优异的爆炸性能，爆压是 TNT（19 GPa）的 4-8 倍，爆速是 TNT 的 1-2 倍（6.90 km s）。电子结构和键合性质表明，Y-N 化合物的高稳定性源于强的 N-N 共价键和弱的 Y-N 离子键相互作用。随着压力降低，转移电荷数量的增加更有利于稳定聚合氮结构，这导致 1̄-II-YN 和 1̄-YN 在环境条件下的亚稳性质。最后，计算了 1̄-II-YN、1̄-YN 和 31-YN 的红外（IR）光谱，为实验合成提供了参考。
