Statistical Mechanics of Si, Al Ordering in A-type Zeolites

Abstract The distribution of Si and Al atoms on the framework of zeolite A is analyzed by the Monte Carlo method for Si/Al ratio from 1 to 3. Atom configurations are generated at 400 K by using an interatomic potential which includes long-range electrostatic interactions. Special emphasis is laid upon the study of thermodynamical variables related with this atom distribution (internal energy, configurational entropy, free energy). Our results indicate that the Si, Al ordering contributes appreciably to stabilize the framework, especially for Si/Al ratio near 1.