Theory 22/Hysteresis & Memory/Crystallisation
Polymorphs Remember Their Route
The claim
Which polymorph crystallises depends on the pathway taken rather than on the final conditions, so the same solution can yield different forms at the same supersaturation.
01Mechanism
The first nucleus sets the form through secondary nucleation; the pathway determines which nucleus appears first, and it persists.
02Prediction
Form should depend on the route to a given condition.
03Refutation
Form determined by final conditions alone would remove the pathway effect.