Sequential Polymerization of Nitrogen at High Pressures

With recent advancements in high-pressure technologies, combined with synchrotron X-ray diffraction, Raman spectroscopy, and density functional theory calculations, the study of crystal structures under high-pressure conditions has progressed rapidly. Among various chemical systems, nitrides have been extensively investigated due to their potential applications as superhard materials, high-energy-density materials, and superconductors. In this review, we summarized the crystal structures and nitrogen polymerization behavior in nitrides synthesized in high-pressure experiments. This overview aims to facilitate the design of new nitrides and enhance understanding of the formation pathways and structural diversity of polynitride compounds.