to extended CON network structure*

CO and N₂ are isoelectronic, which have similar melting temperatures, phase transitions, and crystal structures at low pressures and undergo similar chemical transformations to extended network structures at high pressures. In this study, we have investigated chemical transformations of CO-N₂ mixtures over a wide range of composition and pressure, using laser-heated diamond anvil cells, Raman spectroscopy, X-ray diffraction and inelastic X-ray Raman scattering. The results show strong evidences for the formation of all singly bonded, extended CON network structures at 30-50 GPa, highlighting a catalytic role of CO in the synthesis of high energy density, nitrogen-rich polymers well below 100 GPa.