Fig. 16

a Crystal structure of form V of Pbtl (space group P2₁/n) and b the closest predicted structure for form V (space group setting P2₁/c) from Ref. [42]. Each structure is viewed along the b-axis, the direction of translation of its C-3 chains. Ethyl and phenyl groups are coloured orange and blue, respectively, and O and H engaged in N–H···O interactions are shown as balls; other H atoms are omitted for clarity. Note the fundamental differences in the packing of neighbouring ab planes composed of C-3 chain pairs