Prediction of metastable phase of the Sc-N system in the N-rich region under high pressure

• Published in: Physical chemistry chemical physics : PCCP 2023-07, Vol.25 (29), p.29-214
• Main Authors: Niu, Shifeng, Liu, Yuanyuan, Yang, Zhenxing, Liu, Shijie, Yao, Zhen
• Format: Article
• Language: English
• Subjects: Charge transfer; Covalent bonds; High pressure; Metastable phases; Nitrogen; Phase diagrams; Structural stability
• ISSN: 1463-9076; 1463-9084
• DOI: 10.1039/d3cp00826f

The prediction of the high-pressure structure of the ScN x system enriches the phase diagram of the Sc-N system: three metastable phase structures ( P 1&cmb.macr;-ScN 8 , P 1-ScN 9 and P 1-ScN 11 ) are proposed in the N-rich region. These structures have novel polymeric nitrogen structures, and enrich the structural types of polymeric nitrogen under pressure. Interestingly, the P 1-ScN 11 phase can be quenched to ambient conditions, and release energy at a relatively mild temperature of 800 K. The larger charge transfer plays an important role in the structural stability by inducing the Sc-N ionic bond interaction and N-N covalent bond interaction. The prominent energy properties of P 1&cmb.macr;-ScN 8 , P 1-ScN 9 and P 1-ScN 11 make them potential candidates in the application of propellants and explosives. Three metastable phase structures ( P 1&cmb.macr;-ScN 8 , P 1-ScN 9 and P 1-ScN 11 ) are proposed in the N-rich region (ScN x ; x  ≥ 8), which have excellent physical and chemical properties, and also enrich the structural evolution behavior of the Sc and N atom under pressure.