Fig. 10From: Specific energy contributions from competing hydrogen-bonded structures in six polymorphs of phenobarbitalN–H···O=C bonded tapes C-3 in polymorph V (a) and C-5 in polymorph VI (b). Ethyl and phenyl groups are omitted for clarity. Hydrogen bonds are drawn as dashed lines; O and H atoms engaged in H-bond interactions are drawn as ballsBack to article page