Brickwork pattern

Calculations based on simple molecular models and the charge density of the layers suggest that sulfopropylated-//-cyclodextrin and carboxyethylated-/3-cyclodextrin are arranged in the interlayer galleries with their conical axis parallel to the layers with a packing structure which is similar to that in crystalline cyclo dextrin complexes, where the molecules are arranged in a brickwork pattern [202]. 

Fig. 3, The packing status of Form I complex (a) The cage type packing system with the brickwork pattern. Only one barbital molecule which is in full lines and circles is drawn in the packing mode. Water molecules are also drawn in full circles, (b) The stacking of 3-CyD(2), barbital and shifted 3-CyD(l ) molecules. Barbital molecule denoted by the asterisk is included in B CyD(2).

The packing of each molecule in the crystal is shown in Fig. 3. The 3-CyD dimers are packed in the manner of the brickwork pattern which is one of the cage type packing structures and has been frequently seen in the 3-CyD inclusion complex structure of the triclinic space group PI. 

Both crystals are formed on the basis of the cage type packing mode with the brickwork pattern so as to fix the guest molecules at the primary hydroxyl side. 

Examples of 2D Symmetry Classes. One thing that distinguishes 2D symmetries from 3D symmetries is that examples of the former are all around us in everyday life. To emphasize this, we shall take four examples from the realm of brickwork. These are shown in Figure 11.10. It will be obvious that these are patterns seen very often, but it may not, perhaps, be obvious just how much symmetry these patterns have. 

Diagonal Bond. Brickwork in which headers are laid to form a pattern of diagonals. 

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