The creation of modulated monoclinic aperiodic composites in n-alkane/urea compounds
- Univ. of Rennes, Rennes (France). Inst. of Physics
- Argonne National Lab. (ANL), Argonne, IL (United States). Advanced Photon Source (APS)
- European Synchrotron Radiation Facility (ESRF), Grenoble (France)
- Kansas State Univ., Manhattan, KS (United States). Dept. of Chemistry
- Univ. of Rennes, Rennes (France). Campus de Beaulieu, Dept. of Physics
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 P6122(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=ch/cg (chost/cguest), 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 P1211(α0γ). We discuss analogies and differences with n-heptane/urea, which also presents a monoclinic, modulated low-temperature phase.
- Research Organization:
- Argonne National Lab. (ANL), Argonne, IL (United States)
- Sponsoring Organization:
- USDOE; National Science Foundation (NSF)
- Grant/Contract Number:
- AC02-06CH11357; CHE-0809845
- OSTI ID:
- 1280921
- Journal Information:
- Zeitschrift fuer Kristallographie. Crystalline Materials, Vol. 230, Issue 1; ISSN 2194-4946
- Publisher:
- De GruyterCopyright Statement
- Country of Publication:
- United States
- Language:
- English
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