A number of exotic structures have been formed through high-pressure chemistry, but applications have been hindered by difficulties in recovering the high-pressure phase to ambient conditions (i.e., one atmosphere and 300 K). Here we use dispersion-corrected density functional theory [PBE- ulg (Perdew-Burke-Ernzerhof flavor of DFT with the universal low gradient correction for long range London dispersion)] to predict that above 60 gigapascal (GPa) the most stable form of N 2 O (the laughing gas in its molecular form) is a one-dimensional polymer with an all-nitrogen backbone analogous to cis -polyacetylene in which alternate N are bonded (ionic covalent) to O. The analogous trans -polymer is only 0.03 ∼ 0.10 eV/molecular unit less stable. Upon relaxation to ambient conditions, both polymers relax below 14 GPa to the same stable nonplanar trans -polymer. The predicted phonon spectrum and dissociation kinetics validates the stability of this trans -poly-NNO at ambient conditions, which has potential applications as a type of conducting nonlinear optical polymer with all-nitrogen chains and as a high-energy oxidizer for rocket propulsion. This work illustrates in silico materials discovery particularly in the realm of extreme conditions (very high pressure or temperature).

Xiao, H., An, Q., Goddard, W. A., Liu, W.-G., & Zybin, S. V. (2013). Formation of the –N(NO)N(NO)– polymer at high pressure and stabilization at ambient conditions. Proceedings of the National Academy of Sciences, 110(14), 5321–5325.