The recent successful synthesis of Pnnm-CN structure inspired researchers to explore new superhard 3D C–N compounds via a similar method, that is, high-pressure and high-temperature experiments involving carbon and nitrogen elements. Naturally, in some past high-pressure experiments involving C–N precursors, whether there are undiscovered C–N compounds in the product is worthy of being re-examined. This work proposed four novel carbon-rich C–N compounds, namely, r-C₁₇N₄, sc-C₄N, sc-C₁₇N₄–I, and sc-C₁₇N₄-II, which possibly coexist with the unidentified simple cubic carbon phase in the shock compression products of the carbon black and tetracyanoethylene mixture. Most of the X-ray diffraction peaks from the experiment could be understood by the proposed C–N compounds. Furthermore, the calculations of formation enthalpies using experimental materials as precursors show that these four C–N compounds are more easily synthesized than the carbon structures previously used to explain the unknown phase. These phenomena indicate that C–N compounds might be synthesized in this experiment, not just the new carbon phase. The current study may provide a new idea for the experimental research of C–N compounds and inspire further research to reevaluate previous experimental findings.

最近Pnnm -CN 结构的成功合成激发了研究人员通过类似的方法探索新的超硬 3D C-N 化合物，即涉及碳和氮元素的高压和高温实验。自然，在以往一些涉及C-N前驱体的高压实验中，产物中是否存在未被发现的C-N化合物值得重新审视。这项工作提出了四种新型富碳 C–N 化合物，即r -C ₁₇ N ₄、sc -C ₄ N、sc -C ₁₇ N ₄ -I 和sc -C ₁₇ N ₄-II，它可能与炭黑和四氰乙烯混合物的冲击压缩产物中未鉴定的简单立方碳相共存。实验中的大部分 X 射线衍射峰都可以通过所提出的 C-N 化合物来理解。此外，使用实验材料作为前体的形成焓计算表明，这四种 C-N 化合物比以前用于解释未知相的碳结构更容易合成。这些现象表明在这个实验中可能合成了 C-N 化合物，而不仅仅是新的碳相。目前的研究可能为C-N化合物的实验研究提供一个新的思路，并激发进一步的研究来重新评估以前的实验结果。