Mechanism of pressure-induced decomposition in ionic compounds

Abstract Pressure, as a fundamental thermodynamic variable, can effectively control the structure and properties of compounds, thereby triggering a series of rich physical and chemical phenomena. This process is also a key approach to deeply understanding the synthesis of unconventional materials and the circulation of matter within planetary interiors. In recent years, researchers have accumulated numerous novel physical and chemical examples under high pressure. Notably, the decomposition of some ionic compounds under high pressure contradicts the traditional notion that pressure always promotes material densification and stability. In this article, we focus on exploring the physical mechanism behind pressure-induced decomposition of ionic compounds from the perspectives of formation enthalpy and interatomic interactions and conclude that ionic compounds composed of elements with similar electronegativities are more prone to decomposition. This provides insight into the study of material properties under extreme conditions and offers a theoretical foundation for the design and preparation of new materials.