Re-examining the crystal structure behaviour of nitrogen and methane
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Date
2020-09-01
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Journal Title
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Volume Title
Publisher
International Union of Crystallography
Abstract
tructures of both methane and nitrogen have previously garnered significant interest, but these investigations tailed off thirty years ago with emphasis being more recently on their high-pressure structures (Neumann et al., 2003[Neumann, M. A., Press, W., Nöldeke, C., Asmussen, B., Prager, M. & Ibberson, R. M. (2003). J. Chem. Phys. 119, 1586-1589.]; Maynard-Casely et al., 2010[Maynard-Casely, H., Bull, C., Guthrie, M., Loa, I., McMahon, M., Gregoryanz, E., Nelmes, R. & Loveday, J. (2010). J. Chem. Phys. 133, 064504.], 2014[Maynard-Casely, H., Lundegaard, L., Loa, I., McMahon, M., Gregoryanz, E., Nelmes, R. & Loveday, J. (2014). J. Chem. Phys. 141, 234313.]; Hanfland et al., 1998[Hanfland, M., Lorenzen, M., Wassilew-Reul, C. & Zontone, F. (1998). Rev. High Press. Sci. Technol., 7, 787-789.]; Stinton et al., 2009[Stinton, G., Loa, I., Lundegaard, L. & McMahon, M. (2009). J. Chem. Phys. 131, 104511.]). In light of the fact that methane and nitrogen have now been confirmed to be important materials for shaping the surface of other planetary bodies, we undertook an investigation to examine their solid-phase behaviour and to determine their thermal expansion. Previous determinations of the thermal linear expansion of methane and nitrogen used a dilatometer, restricted to the range 4.2–40 K for nitrogen (Heberlein et al., 1970[Heberlein, D., Adams, E. & Scott, T. (1970). J. Low Temp. Phys. 2, 449-463.]) and 4–26 K for methane (Heberlein & Adams, 1970[Heberlein, D. & Adams, E. (1970). J. Low Temp. Phys. 3, 115-121.]; Manzhelii et al., 1969[Manzhelii, V., Tolkachev, A. & Gavrilko, V. (1969). J. Phys. Chem. Solids, 30, 2759-2763.]). In the present study, we determined the volume change and derived the linear expansion from neutron diffraction data, encompassing the whole range of Pluto temperatures (24 to 54 K) while also allowing insights into their crystal structures. © The Authors
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Keywords
Molecular crystals, Pluto planet, Thermal expansion, Methane, Crystal structure, Crystal-phase transformations
Citation
Maynard-Casely, H. E., Hester, J. R., & Brand, H. E. A. (2020). Re-examining the crystal structure behaviour of nitrogen and methane. IUCrJ, 7(5), 844-851. doi: 10.1107/S2052252520007460