Nitrogen Hydrate Cage Occupancy and Bulk Modulus Inferred from Density Functional Theory-Derived Cell Parameters

• Published in: The Journal of Physical Chemistry C
• Main Authors: Métais, C., Petuya, C., Espert, S., Ollivier, J., Martin-Gondre, L., Desmedt, A.
• Other Authors: Univers, Transport, Interfaces, Nanostructures, Atmosphère et environnement, Molécules (UMR 6213) (UTINAM), Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS)-Université de Franche-Comté (UFC), Université Bourgogne Franche-Comté COMUE (UBFC)-Université Bourgogne Franche-Comté COMUE (UBFC), Institut des Sciences Moléculaires (ISM), Université Montesquieu - Bordeaux 4-Université Sciences et Technologies - Bordeaux 1 (UB)-École Nationale Supérieure de Chimie et de Physique de Bordeaux (ENSCPB)-Institut de Chimie du CNRS (INC)-Centre National de la Recherche Scientifique (CNRS), Institut Laue-Langevin (ILL), Donostia International Physics Center (DIPC), University of the Basque Country/Euskal Herriko Unibertsitatea (UPV/EHU)
• Format: Article in Journal/Newspaper
• Language: English
• Published: HAL CCSD 2021
• Subjects: Clathrate hydrates; DFT - Density Functional Theory; Structural / thermomechanical properties; Energetic properties; [CHIM.THEO]Chemical Sciences/Theoretical and/or physical chemistry; [CHIM.MATE]Chemical Sciences/Material chemistry; [PHYS.COND.CM-MS]Physics [physics]/Condensed Matter [cond-mat]/Materials Science [cond-mat.mtrl-sci]; permafrost
• Online Access: https://hal.science/hal-03193914; https://hal.science/hal-03193914/document; https://hal.science/hal-03193914/file/DFT-N2_JPCC_submission_rev.pdf; https://doi.org/10.1021/acs.jpcc.1c00244

International audience Gas clathrate hydrate solid materials, ubiquitous in nature as found either on the ocean floor, permafrost on the Earth, or in extraterrestrial planets and comets, are also technologically relevant, for example, in energy storage or carbon dioxide sequestration. Nitrogen hydrate, in particular, is of great interest as a promoter of the kinetics of the methane replacement reaction by carbon dioxide in natural gas hydrates. This hydrate may also appear in the chemistry of planets wherever nitrogen constitutes the majority of the atmosphere. A fine understanding of the stability of this hydrate under various thermodynamic conditions is thus of utmost importance to assess its role in the many fields where it is used. In the present work, we have investigated the structural properties of nitrogen hydrate by means of density functional theory calculations. We show that the lattice parameters strongly depend on the cage occupancy and that sI structure has higher bulk elasticity than the sII structure. An energy analysis reveals the key role played by the cage occupancy on the type of hydrate structure formed, which could be used for experimentally estimating the cage occupancy through the lattice parameter measurement.