The search for the stable polymeric forms of solid nitrogen is of great importance in view of its poten-tial application as a high-energy-density material. Using first principles calculations combined with an effective crystal structure search method, we demonstrate that nitrogen can react with methane under rel-atively moderate pressures. The structures and the stability strongly depend on the composition. CN2H4 and CN4H4 compounds become stable in Pca21 and I-42d phases under pressures of 11 and 41 GPa, re-spectively. Especially, CN4H4 is recoverable as a metastable high energy material at ambient condition, and can release enormous amount of energy (6.43 kJg-1) while decomposing to molecular nitrogen and methane.

中文翻译：

---

甲烷和氮气在高压下反应可回收的高能化合物

鉴于其作为高能量密度材料的潜在应用，寻求稳定的固态氮聚合物形式具有重要意义。使用第一原理计算与有效的晶体结构搜索方法相结合，我们证明了氮气可以在相对中等的压力下与甲烷反应。结构和稳定性强烈取决于组成。CN2H4和CN4H4化合物分别在11 GPa和41 GPa的压力下在Pca21和I-42d相中变得稳定。尤其是，CN4H4在环境条件下可作为亚稳态高能材料回收，并在分解为分子氮和甲烷的同时释放大量能量（6.43 kJg-1）。