Disorder versus structure analysis in intergrowth urea inclusion compounds

Alkane/urea inclusion compounds constitute a class of incommensurate compos ite materials, characterized by a pronounced one dimensional character and strong disorder of the alkane molecules. Intrinsic features of the alkane m olecular form factor can be used to obtain a quantitative interpretation of the alkane subsystem translational degree of freedom whereas they lead to the restriction of observable Bragg reflections. A rigid body approach is a lso presented, which gives a simple description of the alkane sublattice mo dulation in the frame of (3 + 1) dimensional structure refinement.