Figure 3.

Crystallographic and local symmetry elements in the bc-plane of 1-I (viewed along the a*-axis). (a–d) Molecules are color coded, yellow (y), blue (b), red (r), and green (g), according to their symmetry relationships: translation (y/y, b/b, r/r, g/g), glide (y/g, r/b), and inversion (y/b, r/g); local and global symmetry elements are indicated red and black, respectively; (a) single H-bonded chain; two neighboring chains related by (b) inversion (X) or (c) by translation (T); (d) X′ X T X′ X T sequence of H-bonded chains; the local symmetry elements α–ε are listed in Table 4; (e) alternative representation of the same sequence, highlighting molecule types 1 (green), 2 (gray), and 3 (pink).