P–V–Tequation of state of synthetic mirabilite (Na2SO4·10D2O) determined by powder neutron diffraction
Fortes, Andrew Dominic and Brand, H.E.A. and Vočadlo, L. and Lindsay-Scott, A. and Fernandez-Alonso, F. and Wood, I.G. (2013) P–V–Tequation of state of synthetic mirabilite (Na2SO4·10D2O) determined by powder neutron diffraction. Journal of Applied Crystallography 46 (2), pp. 448-460. ISSN 0021-8898.
Abstract
Neutron powder diffraction data have been collected from Na2SO4·10D2O (the deuterated analogue of mirabilite), a highly hydrated sulfate salt that is thought to be a candidate rock-forming mineral in some icy satellites of the outer solar system. These measurements, made using the OSIRIS instrument on the ISIS neutron spallation source, covered the range 0.1 < P < 545 MPa and 150 < T < 270 K. The refined unit-cell volumes as a function of pressure and temperature are parameterized in the form of a Birch–Murnaghan third-order equation of state, and the anisotropic linear incompressibilities are represented in terms of the elastic strain tensor. At 270 K, the bulk modulus K0,270 = 19.6 (1) GPa, its first pressure derivative ∂K/∂P = 5.8 (5) and its temperature dependence ∂K/∂T = −0.0175 (6) GPa K−1. The stiffest direction at 270 K, with a linear bulk modulus of ∼82 GPa, is coincident with the twofold axis of this monoclinic crystal. Of the remaining two principal directions, the most compressible (K≃ 44 GPa) is roughly aligned with the c axis, and the intermediate value (K≃ 59 GPa) is therefore approximately collinear with a*. With the aid of additional published data, a number of other important thermodynamic quantities have been derived, including the Grüneisen and Anderson–Grüneisen parameters, and the volume and enthalpy of melting along the high-pressure melting curve. Additional data obtained during this work, concerning the elastic properties of deuterated ice IV, are also presented.
Metadata
Item Type: | Article |
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Keyword(s) / Subject(s): | mirabilite, equations of state, neutron diffraction, ice IV |
School: | Birkbeck Faculties and Schools > Faculty of Science > School of Natural Sciences |
Depositing User: | Administrator |
Date Deposited: | 06 Jun 2013 15:33 |
Last Modified: | 02 Aug 2023 17:05 |
URI: | https://eprints.bbk.ac.uk/id/eprint/7327 |
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