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Title: The crystal structure of methane B at 8 GPa—An α-Mn arrangement of molecules

Abstract

From a combination of powder and single-crystal synchrotron x-ray diffraction data we have determined the carbon substructure of phase B of methane at a pressure of ∼8 GPa. We find this substructure to be cubic with space group I4{sup ¯}3m and 58 molecules in the unit cell. The unit cell has a lattice parameter a = 11.911(1) Å at 8.3(2) GPa, which is a factor of √2 larger than had previously been proposed by Umemoto et al. [J. Phys.: Condens. Matter 14, 10675 (2002)]. The substructure as now solved is not related to any close-packed arrangement, contrary to previous proposals. Surprisingly, the arrangement of the carbon atoms is isostructural with that of α-manganese at ambient conditions.

Authors:
; ; ; ; ;  [1]
  1. SUPA, School of Physics and Astronomy and Centre for Science at Extreme Conditions, The University of Edinburgh, Edinburgh EH9 3JZ (United Kingdom)
Publication Date:
OSTI Identifier:
22413342
Resource Type:
Journal Article
Journal Name:
Journal of Chemical Physics
Additional Journal Information:
Journal Volume: 141; Journal Issue: 23; Other Information: (c) 2014 AIP Publishing LLC; Country of input: International Atomic Energy Agency (IAEA); Journal ID: ISSN 0021-9606
Country of Publication:
United States
Language:
English
Subject:
37 INORGANIC, ORGANIC, PHYSICAL AND ANALYTICAL CHEMISTRY; CARBON; CRYSTAL STRUCTURE; LATTICE PARAMETERS; MANGANESE; METHANE; MOLECULES; MONOCRYSTALS; POWDERS; PROPOSALS; SPACE GROUPS; SYNCHROTRONS; X-RAY DIFFRACTION

Citation Formats

Maynard-Casely, H. E., E-mail: helen.maynard-casely@ansto.gov.au, Lundegaard, L. F., Loa, I., McMahon, M. I., Gregoryanz, E., Nelmes, R. J., and Loveday, J. S. The crystal structure of methane B at 8 GPa—An α-Mn arrangement of molecules. United States: N. p., 2014. Web. doi:10.1063/1.4903813.
Maynard-Casely, H. E., E-mail: helen.maynard-casely@ansto.gov.au, Lundegaard, L. F., Loa, I., McMahon, M. I., Gregoryanz, E., Nelmes, R. J., & Loveday, J. S. The crystal structure of methane B at 8 GPa—An α-Mn arrangement of molecules. United States. https://doi.org/10.1063/1.4903813
Maynard-Casely, H. E., E-mail: helen.maynard-casely@ansto.gov.au, Lundegaard, L. F., Loa, I., McMahon, M. I., Gregoryanz, E., Nelmes, R. J., and Loveday, J. S. 2014. "The crystal structure of methane B at 8 GPa—An α-Mn arrangement of molecules". United States. https://doi.org/10.1063/1.4903813.
@article{osti_22413342,
title = {The crystal structure of methane B at 8 GPa—An α-Mn arrangement of molecules},
author = {Maynard-Casely, H. E., E-mail: helen.maynard-casely@ansto.gov.au and Lundegaard, L. F. and Loa, I. and McMahon, M. I. and Gregoryanz, E. and Nelmes, R. J. and Loveday, J. S.},
abstractNote = {From a combination of powder and single-crystal synchrotron x-ray diffraction data we have determined the carbon substructure of phase B of methane at a pressure of ∼8 GPa. We find this substructure to be cubic with space group I4{sup ¯}3m and 58 molecules in the unit cell. The unit cell has a lattice parameter a = 11.911(1) Å at 8.3(2) GPa, which is a factor of √2 larger than had previously been proposed by Umemoto et al. [J. Phys.: Condens. Matter 14, 10675 (2002)]. The substructure as now solved is not related to any close-packed arrangement, contrary to previous proposals. Surprisingly, the arrangement of the carbon atoms is isostructural with that of α-manganese at ambient conditions.},
doi = {10.1063/1.4903813},
url = {https://www.osti.gov/biblio/22413342}, journal = {Journal of Chemical Physics},
issn = {0021-9606},
number = 23,
volume = 141,
place = {United States},
year = {Sun Dec 21 00:00:00 EST 2014},
month = {Sun Dec 21 00:00:00 EST 2014}
}