The creation of modulated monoclinic aperiodic composites in n-alkane/urea compounds
| Autor: | Philippe Rabiller, Bertrand Toudic, Laurent Guérin, Céline Mariette, Yu-Sheng Chen, Mark D. Hollingsworth, Alexander Popov, Alexei Bosak |
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| Přispěvatelé: | Institut de Physique de Rennes (IPR), Université de Rennes (UR)-Centre National de la Recherche Scientifique (CNRS), Argonne National Laboratory [Lemont] (ANL), European Synchrotron Radiation Facility (ESRF), Kansas State University, We thank Shane M. Nichols, Bo Wang, Robert Henning, and Vukica Srager for their help with this work, which was supported by the NSF (CHE-0809845). Portions of this research were carried out at the Advanced Photon Source (beamline 14-BM-C) at Argonne National Laboratory, under DOE Contract No. DE-AC02-06CH11357., Université de Rennes 1 (UR1), Université de Rennes (UNIV-RENNES)-Université de Rennes (UNIV-RENNES)-Centre National de la Recherche Scientifique (CNRS) |
| Jazyk: | angličtina |
| Rok vydání: | 2015 |
| Předmět: |
Alkane
chemistry.chemical_classification alkane/urea crystals [PHYS]Physics [physics] Phase transition diffraction aperiodic crystals Condensed Matter Physics Superspace Article phase transitions Inorganic Chemistry chemistry.chemical_compound Crystallography chemistry Group (periodic table) Phase (matter) crystallographic superspace Urea Molecule General Materials Science Monoclinic crystal system |
| Zdroj: | Zeitschrift für Kristallographie Zeitschrift für Kristallographie, 2015, 230 (1), pp.5--11. ⟨10.1515/zkri-2014-1773⟩ Zeitschrift für Kristallographie, De Gruyter, 2015, 230 (1), pp.5--11. ⟨10.1515/zkri-2014-1773⟩ |
| ISSN: | 0044-2968 2366-1798 |
| DOI: | 10.1515/zkri-2014-1773⟩ |
| Popis: | n-Dodecane/urea is a member of the prototype series of n-alkane/urea inclusion compounds. At room temperature, it presents a quasi-one dimensional liquid-like state for the confined guest molecules within the rigid, hexagonal framework of the urea host. At lower temperatures, we report the existence of two other phases. Below Tc=248 K there appears a phase with rank four superspace group P61 22(00γ), the one typically observed at room temperature in n-alkane/urea compounds with longer guest molecules. A misfit parameter, defined by the ratio γ= c h/c g (c host/c guest), is found to be 0.632±0.005. Below Tc1=123 K, a monoclinic modulated phase is created with a constant shift along c of the guest molecules in adjacent channels. The maximal monoclinic space group for this structure is P121 1(α0γ). Analogies and differences with n-heptane/urea, which also presents a monoclinic, modulated low-temperature phase, are discussed. |
| Databáze: | OpenAIRE |
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