Pressure‐Driven Reactivity in Dense Methane‐Nitrogen Mixtures

Abstract

Abstract Carbon, nitrogen, and hydrogen are among the most abundant elements in the solar system, and our understanding of their interactions is fundamental to prebiotic chemistry. CH 4 and N 2 are the simplest archetypical molecules formed by these elements and are both markedly stable under extremes of pressure. Through a series of diamond anvil cell experiments supported by density functional theory calculations, we observe diverse compound formation and reactivity in the CH 4 ‐N 2 binary system at high pressure. Above 7 GPa two concentration‐dependent molecular compounds emerge, (CH 4 ) 5 N 2 and (CH 4 ) 7 (N 2 ) 8 , held together by weak van der Waals interactions. Strikingly, further compression at room temperature irreversibly breaks the N 2 triple bond, inducing the dissociation of CH 4 above 140 GPa, with the near‐quenched samples revealing distinct spectroscopic signatures of strong covalently bonded C−N−H networks. High temperatures vastly reduce the required pressure to promote the reactivity between CH 4 and N 2 , with NH 3 forming together with longer‐chain hydrocarbons at 14 GPa and 670 K, further decomposing into powdered diamond when temperatures exceed 1200 K. These results exemplify how pressure‐driven chemistry can cause unexpected complexity in the most simple molecular precursors.