Understanding the Effect of a Solvent on the Crystal Habit

The extreme polar morphology that has been observed for crystals of the stable form of a steroid is explained by a molecular dynamics simulations approach. The habit modification is caused by surface−solvent interactions, which affect the growth rate of the polar faces differently. The same effect was observed for the metastable polymorphic form. Depending on the solvent, the nature of the difference is mainly caused by the hydrogen bond interactions or the electrostatic part of the interactions.