Fig. 4.

Results of SCDS-PIXEL calculations for polymorph X. a Interaction energies, represented by balls, are separated into internal C-1 interactions (blue) and chain–chain contacts (highlighted @1, red; @2, orange; @3, green). The horizontal bars indicate cumulative PIXEL energies (summation from left to right) relative to E _T,Cry (scale on the right-hand side). b The eight most important pairwise interactions involving a central molecule (orange). The mean plane of the pyrimidine ring of the central molecule is drawn, H atoms are omitted for clarity and H-bonds are indicated by blue lines