Accessing new polymorphs and solvates through solvothermal recrystallization.

In high-pressure structural chemistry, recrystallization techniques have been shown to be a powerful way of generating new polymorphs and solvates. A recent study by Olejniczak et al. [ IUCrJ (2022), 9 , 49-54] on the pyridazine-based compound 6-chloro-1,2,3,4-tetrazolo[1,5- b ]pyridazine (C 4 H 2 N 5 Cl or CTP) uses these solvothermal techniques to establish the phase behaviour of CTP and the effects of partial hydration.