Considering that pressure-induced formation of short, strong covalent bonds in light-element compounds can produce superhard materials, we employ structure searching and first-principles calculations to predict a new class of boron nitrides with a stoichiometry of BN₂, which are stable relative to alpha-B and alpha-N₂ at ambient pressure. At ambient pressure, the most stable phase has a layered structure (h-BN₂) containing hexagonal BN layers between which there are intercalated N₂ molecules. At 25 GPa, a three-dimensional P4₂/mmc structure with single N–N bonds becomes the most stable. Dynamical, thermal, and mechanical stability calculations reveal that this structure can be recovered under ambient conditions. Its calculated stress-strain relations demonstrate an intrinsic superhard nature with an estimated Vickers hardness of ∼43 GPa. This structure has a potentially high energy density of ∼4.19 kJ/g.

考虑到在轻元素化合物中压力诱导形成短而强的共价键可以产生超硬材料，我们采用结构搜索和第一性原理计算来预测一类具有 BN ₂化学计量的新型氮化硼，它们相对稳定。在环境压力下转化为 alpha-B 和 alpha-N _{2 。}在环境压力下，最稳定的相具有层状结构 (h-BN ₂ )，其中包含六方 BN 层，在这些层之间有插入的 N ₂分子。在 25 GPa 时，三维P 4 ₂ / mmc单 N-N 键的结构变得最稳定。动态、热和机械稳定性计算表明，这种结构可以在环境条件下恢复。其计算的应力-应变关系显示出固有的超硬性质，估计维氏硬度为~43 GPa。这种结构具有潜在的高能量密度，约为 4.19 kJ/g。