Ab initio study of the initial steps of hydrothermal zeolite synthesis and of sol-gel processes

The initial steps of hydrothermal zeolite synthesis and of sol-gel processes were studied by ab initio calculation of molecular models representing the reagents, intermediates and final products of the reactions. The calculations show that the anionic compounds are more stable than the corresponding neutral compounds. It is proposed that the reaction mechanism involves the polycondensation of anionic species with the subsequent formation of both linear and cyclic chains. (C) 1997 Elsevier Science B.V.