Longitudinal positional ordering of n-alkane molecules in urea inclusion compounds

Weber, T.; Boysen, Hans und Frey, Friedrich (2000): Longitudinal positional ordering of n-alkane molecules in urea inclusion compounds. In: Acta Crystallographica Section B: Structural Science, Bd. 56, Nr. 1: S. 132-141

Abstract

The profiles of diffuse layers, which are present in diffraction patterns of urea inclusion compounds, are interpreted quantitatively by a longitudinal positional paracrystalline order of the alkane guest molecules within the channels of the urea-host framework structure, in agreement with the expected behaviour of a one-dimensional system. With decreasing temperature there is a gradual transition into long-range order behaviour. This ordering process remains unaffected by structural changes related to lateral correlations within and between both host and guest substructures, including a structural phase transformation. The differing behaviour of a mixed system (pentadecane/hexadecane) with average period almost commensurate with the urea host lattice is explained by the superposition of main and satellite layers. The distribution of both molecules within each tunnel is random.

• Dokumententyp: Zeitschriftenartikel
• Fakultät: Geowissenschaften > Department für Geo- und Umweltwissenschaften > Kristallographie und Materialwissenschaft
• Themengebiete: 500 Naturwissenschaften und Mathematik > 550 Geowissenschaften, Geologie
• Sprache: Englisch