Ambient-Condition Recoverable Polymeric N₁₀ Discovered from the Predicted Zr-N Compounds

Polynitrogen has been widely studied recently as a rising star of high energy density materials. Here, we performed a systematic study of the Zr-N compounds in the N-rich region by the first-principles method. The high-pressure phase diagram of the Zr-N system is enriched by proposing five new compounds. ZrN₁₀ with the infinitely extended band shaped structure is first reported. The band-like polynitrogen of ZrN₁₀ decomposes into a more stable chain-like polynitrogen structure under the influence of temperature. Additionally, the novel honeycomb-like band-shaped N₁₀ structure hcb-N₁₀ has been discovered by removing the Zr atoms. The absence of the -4 oxidation state in the N₁₀ unit prompts its further polymerization, which makes hcb-N₁₀ possess dynamical and thermal stability in ambient conditions. hcb-N₁₀ is a semiconductor with a bandgap of 2.97 eV due to highly localized electrons. Both chain-ZrN₁₀ and hcb-N₁₀ represent potential candidates for HEDMs with outstanding energy and explosive performance.