Multi-Scale Transformation of Nitrous Oxide into Functional Materials under Extreme Conditions: A Framework from High-Pressure Polymerization to Radiation-Induced Synthesis

Nitrous oxide (N₂O), a potent and chemically inert greenhouse gas, represents a dual challenge of environmental concern and untapped materials potential. This critical review establishes a unified, multi-scale framework for the forced transformation of stable small moleculesexemplified by N₂O-into functional nitrogen-oxygen-carbon (N-O-C) materials via extremecondition synthesis. We systematically evaluate and integrate four primary activation pathways: high-pressure polymerization, cryogenic matrix isolation, high-temperature molten salt transport, and radiation-induced synthesis. The review synthesizes foundational principles and recent advances in each domain, highlighting the indispensable role of multi-scale computational modeling (DFT, MD, GEANT4) in guiding and validating experimental discovery. Using N₂O as a detailed case study, we demonstrate how the convergence of these disparate techniques enables the coercive formation of polymeric (N₂O)ₙ phases, metastable isomers (ONCO), and radiation-modified hybrids. The proposed framework not only charts a viable route to valorize N₂O into materials for energy storage, catalysis, and sensing but also provides a blueprint for activating other recalcitrant molecules (CO₂, CH₄). We conclude by identifying critical challenges in metastability, scalable synthesis, and in-operando characterization, outlining a forward-looking research agenda that bridges environmental remediation with nextgeneration materials design.