Fig. 8.

Results of SCDS-PIXEL calculations for polymorph I. a Interaction energies, represented by balls, are separated into internal L-3 (blue) interactions, internal C-2 (red) interactions, interactions between a L-3 layer and a stack of C-2 chains (@1, orange) and interactions between neighbouring C-2 (@2, green; @3, beige). The horizontal bars indicate cumulative PIXEL energies (summation from left to right) relative to the E _T,Cry (scale on the right-hand side). b–d A central molecule A, B or C (coloured orange) and neighbouring molecules involved in six (b, c) or seven (d) pairwise interactions (see Additional file 1: Tables S1–S3). 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