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Nitrogen oxides under pressure: stability, ionization, polymerization, and superconductivity.

ABSTRACT: Nitrogen oxides are textbook class of molecular compounds, with extensive industrial applications. Nitrogen and oxygen are also among the most abundant elements in the universe. We explore the N-O system at 0 K and up to 500 GPa though ab initio evolutionary simulations. Results show that two phase transformations of stable molecular NO2 occur at 7 and 64 GPa, and followed by decomposition of NO2 at 91 GPa. All of the NO(+)NO3(-) structures are found to be metastable at T = 0 K, so experimentally reported ionic NO(+)NO3(-) is either metastable or stabilized by temperature. N2O5 becomes stable at 9 GPa, and transforms from P-1 to C2/c structure at 51 GPa. NO becomes thermodynamically stable at 198 GPa. This polymeric phase is superconducting (Tc = 2.0 K) and contains a -N-N- backbone.

SUBMITTER: Li D

PROVIDER: S-EPMC4648296 | biostudies-literature | 2015 Nov

REPOSITORIES: biostudies-literature

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Nitrogen oxides under pressure: stability, ionization, polymerization, and superconductivity.

Li Dongxu D Oganov Artem R AR Dong Xiao X Zhou Xiang-Feng XF Zhu Qiang Q Qian Guangrui G Dong Huafeng H

Scientific reports 20151117

Nitrogen oxides are textbook class of molecular compounds, with extensive industrial applications. Nitrogen and oxygen are also among the most abundant elements in the universe. We explore the N-O system at 0 K and up to 500 GPa though ab initio evolutionary simulations. Results show that two phase transformations of stable molecular NO2 occur at 7 and 64 GPa, and followed by decomposition of NO2 at 91 GPa. All of the NO(+)NO3(-) structures are found to be metastable at T = 0 K, so experimentall ...[more]

PMID: 26575799

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