| Autor: |
Pakhomova A; Deutsches Elektronen-Synchrotron (DESY), 22607 Hamburg, Germany.; European Synchrotron Radiation Facility, 38000 Grenoble, France., Collings IE; European Synchrotron Radiation Facility, 38000 Grenoble, France., Journaux B; Department of Earth and Space Science, University of Washington, Seattle, Washington 98195, United States., Petitgirard S; Institute of Geochemistry and Petrology, ETH Zürich, 8092 Zürich, Switzerland., Boffa Ballaran T; Bayerisches Geoinstitut, University of Bayreuth, 95440 Bayreuth, Germany., Huang D; Institute of Geochemistry and Petrology, ETH Zürich, 8092 Zürich, Switzerland., Ott J; Department of Earth and Space Science, University of Washington, Seattle, Washington 98195, United States., Kurnosov A; Bayerisches Geoinstitut, University of Bayreuth, 95440 Bayreuth, Germany., Hanfland M; European Synchrotron Radiation Facility, 38000 Grenoble, France., Garbarino G; European Synchrotron Radiation Facility, 38000 Grenoble, France., Comboni D; European Synchrotron Radiation Facility, 38000 Grenoble, France. |
| Abstrakt: |
The phenomenon of host-guest hydrogen bonding in clathrate hydrate crystal structures and its effect on physical and chemical properties have become subjects of extensive research. Hydrogen bonding has been studied for cubic (sI and sII) and hexagonal (sH) binary clathrates, while it has not been addressed for clathrate structures that exist at elevated pressures. Here, four acetone hydrate clathrates have been grown at high-pressure and low-temperature conditions. In situ single-crystal X-ray diffraction revealed that the synthesized phases possess already known trigonal (sTr), orthorhombic (sO), and tetragonal (sT) crystal structures as well as a previously unknown orthorhombic structure, so-called sO-II. Only sO and sII have previously been reported for acetone clathrates. Structural analysis suggests that acetone oxygens are hydrogen-bonded to the closest water oxygens of the host frameworks. Our discoveries show that clathrate hydrates hosting polar molecules are not as exotic as previously thought and could be stabilized at high-pressure conditions through hydrogen bonding. |
