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Title: High-pressure polymorphism in pyridine

Abstract

Single crystals of the high-pressure phases II and III of pyridine have been obtained by in situ crystallization at 1.09 and 1.69 GPa, revealing the crystal structure of phase III for the first time using X-ray diffraction. Phase II crystallizes in P 2 1 2 1 2 1 with Z ′ = 1 and phase III in P 4 1 2 1 2 with Z ′ = ½. Neutron powder diffraction experiments using pyridine-d 5 establish approximate equations of state of both phases. The space group and unit-cell dimensions of phase III are similar to the structures of other simple compounds with C 2v molecular symmetry, and the phase becomes stable at high pressure because it is topologically close-packed, resulting in a lower molar volume than the topologically body-centred cubic phase II. Phases II and III have been observed previously by Raman spectroscopy, but have been mis-identified or inconsistently named. Raman spectra collected on the same samples as used in the X-ray experiments establish the vibrational characteristics of both phases unambiguously. The pyridine molecules interact in both phases through CH...π and CH...N interactions. The nature of individual contacts is preserved through the phase transition between phases III and II, which occursmore » on decompression. A combination of rigid-body symmetry mode analysis and density functional theory calculations enables the soft vibrational lattice mode which governs the transformation to be identified.« less

Authors:
; ; ; ; ; ORCiD logo; ; ; ;
Publication Date:
Sponsoring Org.:
USDOE
OSTI Identifier:
1577894
Resource Type:
Published Article
Journal Name:
IUCrJ
Additional Journal Information:
Journal Name: IUCrJ Journal Volume: 7 Journal Issue: 1; Journal ID: ISSN 2052-2525
Publisher:
International Union of Crystallography (IUCr)
Country of Publication:
United Kingdom
Language:
English

Citation Formats

Giordano, Nico, Beavers, Christine M., Campbell, Branton J., Eigner, Václav, Gregoryanz, Eugene, Marshall, Willliam G., Peña-Álvarez, Miriam, Teat, Simon J., Vennari, Cara E., and Parsons, Simon. High-pressure polymorphism in pyridine. United Kingdom: N. p., 2020. Web. doi:10.1107/S2052252519015616.
Giordano, Nico, Beavers, Christine M., Campbell, Branton J., Eigner, Václav, Gregoryanz, Eugene, Marshall, Willliam G., Peña-Álvarez, Miriam, Teat, Simon J., Vennari, Cara E., & Parsons, Simon. High-pressure polymorphism in pyridine. United Kingdom. doi:10.1107/S2052252519015616.
Giordano, Nico, Beavers, Christine M., Campbell, Branton J., Eigner, Václav, Gregoryanz, Eugene, Marshall, Willliam G., Peña-Álvarez, Miriam, Teat, Simon J., Vennari, Cara E., and Parsons, Simon. Wed . "High-pressure polymorphism in pyridine". United Kingdom. doi:10.1107/S2052252519015616.
@article{osti_1577894,
title = {High-pressure polymorphism in pyridine},
author = {Giordano, Nico and Beavers, Christine M. and Campbell, Branton J. and Eigner, Václav and Gregoryanz, Eugene and Marshall, Willliam G. and Peña-Álvarez, Miriam and Teat, Simon J. and Vennari, Cara E. and Parsons, Simon},
abstractNote = {Single crystals of the high-pressure phases II and III of pyridine have been obtained by in situ crystallization at 1.09 and 1.69 GPa, revealing the crystal structure of phase III for the first time using X-ray diffraction. Phase II crystallizes in P 2 1 2 1 2 1 with Z ′ = 1 and phase III in P 4 1 2 1 2 with Z ′ = ½. Neutron powder diffraction experiments using pyridine-d 5 establish approximate equations of state of both phases. The space group and unit-cell dimensions of phase III are similar to the structures of other simple compounds with C 2v molecular symmetry, and the phase becomes stable at high pressure because it is topologically close-packed, resulting in a lower molar volume than the topologically body-centred cubic phase II. Phases II and III have been observed previously by Raman spectroscopy, but have been mis-identified or inconsistently named. Raman spectra collected on the same samples as used in the X-ray experiments establish the vibrational characteristics of both phases unambiguously. The pyridine molecules interact in both phases through CH...π and CH...N interactions. The nature of individual contacts is preserved through the phase transition between phases III and II, which occurs on decompression. A combination of rigid-body symmetry mode analysis and density functional theory calculations enables the soft vibrational lattice mode which governs the transformation to be identified.},
doi = {10.1107/S2052252519015616},
journal = {IUCrJ},
number = 1,
volume = 7,
place = {United Kingdom},
year = {2020},
month = {1}
}

Journal Article:
Free Publicly Available Full Text
Publisher's Version of Record
DOI: 10.1107/S2052252519015616

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