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Experiments indicating a second hydrogen ordered phase of ice VI
In the last twelve years five new ice phases were experimentally prepared. Two of them are empty clathrate hydrates and three of them represent hydrogen ordered counterparts of previously known disordered ice phases. Here, we report on hydrogen ordering in ice VI samples produced by cooling at press...
Autores principales: | , , , , , , |
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Formato: | Online Artículo Texto |
Lenguaje: | English |
Publicado: |
Royal Society of Chemistry
2018
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Materias: | |
Acceso en línea: | https://www.ncbi.nlm.nih.gov/pmc/articles/PMC5942039/ https://www.ncbi.nlm.nih.gov/pubmed/29780552 http://dx.doi.org/10.1039/c8sc00135a |
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author | Gasser, Tobias M. Thoeny, Alexander V. Plaga, Lucie J. Köster, Karsten W. Etter, Martin Böhmer, Roland Loerting, Thomas |
author_facet | Gasser, Tobias M. Thoeny, Alexander V. Plaga, Lucie J. Köster, Karsten W. Etter, Martin Böhmer, Roland Loerting, Thomas |
author_sort | Gasser, Tobias M. |
collection | PubMed |
description | In the last twelve years five new ice phases were experimentally prepared. Two of them are empty clathrate hydrates and three of them represent hydrogen ordered counterparts of previously known disordered ice phases. Here, we report on hydrogen ordering in ice VI samples produced by cooling at pressures up to 2.00 GPa. Based on results from calorimetry, dielectric relaxation spectroscopy, Raman spectroscopy, and powder X-ray diffraction the existence of a second hydrogen ordered polymorph related to ice VI is suggested. Powder X-ray data show the oxygen network to be the one of ice VI. For the 1.80 GPa sample the activation energy from dielectric spectroscopy is 45 kJ mol(–1), which is much larger than for the known hydrogen ordered proxy of ice VI, ice XV. Raman spectroscopy indicates the 1.80 GPa sample to be more ordered than ice XV. It is further distinct from ice XV in that it experiences hydrogen disordering above ≈103 K which is 26 K below the ice XV to ice VI disordering transition. Consequently, below 103 K it is thermodynamically more stable than ice XV, adding a stability region to the phase diagram of water. For the time being we suggest to call this new phase ice β-XV and to relabel it ice XVIII once its crystal structure is known. |
format | Online Article Text |
id | pubmed-5942039 |
institution | National Center for Biotechnology Information |
language | English |
publishDate | 2018 |
publisher | Royal Society of Chemistry |
record_format | MEDLINE/PubMed |
spelling | pubmed-59420392018-05-18 Experiments indicating a second hydrogen ordered phase of ice VI Gasser, Tobias M. Thoeny, Alexander V. Plaga, Lucie J. Köster, Karsten W. Etter, Martin Böhmer, Roland Loerting, Thomas Chem Sci Chemistry In the last twelve years five new ice phases were experimentally prepared. Two of them are empty clathrate hydrates and three of them represent hydrogen ordered counterparts of previously known disordered ice phases. Here, we report on hydrogen ordering in ice VI samples produced by cooling at pressures up to 2.00 GPa. Based on results from calorimetry, dielectric relaxation spectroscopy, Raman spectroscopy, and powder X-ray diffraction the existence of a second hydrogen ordered polymorph related to ice VI is suggested. Powder X-ray data show the oxygen network to be the one of ice VI. For the 1.80 GPa sample the activation energy from dielectric spectroscopy is 45 kJ mol(–1), which is much larger than for the known hydrogen ordered proxy of ice VI, ice XV. Raman spectroscopy indicates the 1.80 GPa sample to be more ordered than ice XV. It is further distinct from ice XV in that it experiences hydrogen disordering above ≈103 K which is 26 K below the ice XV to ice VI disordering transition. Consequently, below 103 K it is thermodynamically more stable than ice XV, adding a stability region to the phase diagram of water. For the time being we suggest to call this new phase ice β-XV and to relabel it ice XVIII once its crystal structure is known. Royal Society of Chemistry 2018-03-26 /pmc/articles/PMC5942039/ /pubmed/29780552 http://dx.doi.org/10.1039/c8sc00135a Text en This journal is © The Royal Society of Chemistry 2018 http://creativecommons.org/licenses/by/3.0/ This article is freely available. This article is licensed under a Creative Commons Attribution 3.0 Unported Licence (CC BY 3.0) |
spellingShingle | Chemistry Gasser, Tobias M. Thoeny, Alexander V. Plaga, Lucie J. Köster, Karsten W. Etter, Martin Böhmer, Roland Loerting, Thomas Experiments indicating a second hydrogen ordered phase of ice VI |
title | Experiments indicating a second hydrogen ordered phase of ice VI |
title_full | Experiments indicating a second hydrogen ordered phase of ice VI |
title_fullStr | Experiments indicating a second hydrogen ordered phase of ice VI |
title_full_unstemmed | Experiments indicating a second hydrogen ordered phase of ice VI |
title_short | Experiments indicating a second hydrogen ordered phase of ice VI |
title_sort | experiments indicating a second hydrogen ordered phase of ice vi |
topic | Chemistry |
url | https://www.ncbi.nlm.nih.gov/pmc/articles/PMC5942039/ https://www.ncbi.nlm.nih.gov/pubmed/29780552 http://dx.doi.org/10.1039/c8sc00135a |
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