Noble gas reactivity induced by high pressure: Physical and chemical insights

For nearly a century, noble gases stood as chemical spectators—present but unreacting, while high pressure has rewritten that identity. By forcibly reconstructing electronic shells, compression transforms these inert elements into reactive constituents, forging compounds that reshape both chemical bonding paradigms and planetary models. For example, Helium, the most inert of all, forms unique superionic phases in giant planets and reacts with deep-Earth minerals under pressure, offering a unified explanation for primordial isotope retention. Interestingly, xenon bonds with iron and nickel under core conditions, establishing a deep-Earth candidate reservoir that provides insights into the missing xenon paradox. These compelling discoveries do more than expand the periodic table; they forge unprecedented connections between high-pressure physics, geoscience, and materials science. This review synthesizes these advances into a unified framework, establishing predictive design principles that not only explain the stability of exotic compounds, but also guide the targeted synthesis of noble gas-bearing functional materials across the pressure landscape.