1.   Crystallization is a process involving the orderly arrangement of chains and is consequently associated with a large negative entropy of activation.

2.   Large stacking exothermicities are associated with large negative entropy changes that ensure that G is small, permitting readily reversible associations in solution.

3.   Hence, molecular associations that give rise to large exothermicities are also associated with large adverse entropy changes, and the two effects work in a compensatory manner.

4.   No internal rotors are restricted in the stacked dimer, but again we see that large adverse entropies of stacking are associated with larger stacking exothermicities.