Nitrogen-hydrogen-oxygen ternary phase diagram: New phases at high pressure from structural prediction

Shi J, Cui W, Botti S, Marques MAL (2018)

Publication Type: Journal article

Publication year: 2018

Journal

Physical Review Materials American Physical Society

Book Volume: 2

Article Number: 023604

Journal Issue: 2

DOI: 10.1103/PhysRevMaterials.2.023604

Abstract

Using an ab initio evolutionary structural search, we predict two novel crystalline phases in the H-N-O ternary phase diagram at high pressure, namely, NOH4 and HNO3 (nitric acid). Our calculations show that the C2/m phase of NOH4 becomes stable at 71 GPa, while the P21/m phase of HNO3 stabilizes at 39 GPa. Both phases remain thermodynamically stable at least up to 150 GPa, the maximum pressure we considered. The C2/m phase of NOH4 contains two O-H layers and one dumbbell cluster layer, formed by two NH3 molecules linked by a N-N covalent bond. The P21/m phase of HNO3 contains a surprising quasiclover layer formed of H-N-O covalent bonds. Further calculations show that both phases are semiconducting, with band gaps of 6.0 and 2.6 eV for NOH4 and NHO3, respectively. Our calculations also confirm that the compound NOH5(NH3H2O) becomes unstable at pressures above 122 GPa, decomposing into NH3 and H2O.

Involved external institutions

Jiangsu Normal University / 江苏师范大学 CN China (CN) European Theoretical Spectroscopy Facility (ETSF) BE Belgium (BE) Friedrich-Schiller-Universität Jena DE Germany (DE)

How to cite

APA:

Shi, J., Cui, W., Botti, S., & Marques, M.A.L. (2018). Nitrogen-hydrogen-oxygen ternary phase diagram: New phases at high pressure from structural prediction. Physical Review Materials, 2(2). https://doi.org/10.1103/PhysRevMaterials.2.023604

MLA:

Shi, Jingming, et al. "Nitrogen-hydrogen-oxygen ternary phase diagram: New phases at high pressure from structural prediction." Physical Review Materials 2.2 (2018).

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