Figure 5.

Crystal lattice organization. (a, b) Tetramer layers 1 and 2 of the crystal expanded into the surroundings by crystal symmetry operators. Molecules 1 and 2 are shown in green and molecules 6 and 7 are shown in grey, which correspond to the colours that are used in Fig. 4 ▶. The unit cell along the frame of a and b is shown with black lines. (c) Packing of the stefin B molecules in the I4 unit cell showing molecules, layers and octamers. Stefin B molecules in octamers ‘()’ and ‘)(’ are shown in green and grey, respectively. Alternatively placed tetramers 0A, 0B, 5A and 5B are shown in blue, red, light blue and light red, respectively. Molecules and tetramer layers are marked with numbers, octamers with braces and stacks with arrows. The average coordinate along the z molecule is shown for each molecule. The green line represents the position of the twofold rotational axis, which corresponds to the crystallographic twofold axis in space group I422 and relates to the alternatively placed pairs of tetramers 0A–0B and 5A–5B.