Summary
  In the present work the role of organic molecules, Ge atoms and fluoride ions in the síntesis of zeolitas has been studied using computational techniques based on Molecular and Quantum Mechanics.
  The interaction between organic molecules and zeolite framework has been used to analyse the role of pentametonium, hexametonium, heptametonium and octametonium in the synthesis of EUO, ITH, IWR e IWW structures.
  The isomorphous substitution Si by Ge in the AST, ASV, BEA, BEC, ISV, ITH, IWR e IWW structures has been studied and analysed the factors involved on it. Morevover, the preferential location of Ge atoms in the D4R units (Double Four Membered Ring) has been rationalized. Finally, the thermodynamic stability of BEA, BEC and ISV structures at different Ge contents has been analyzed. 
  The location and role of fluoride ions has been studied attending to the factors involved in the fluoride distribution in the pure silica IFR, ITH, STF, and STT structures. Subsequently, the fluoride distribution has been analyzed with the organic cations present inside the zeolite framework. The knowledge about fluoride ions as structure directing agents was used to study the fluoride distribution in the pure silica IWR structure where experimental location of fluoride ions is not completely known.
  The 19F NMR spectrum of fluoride ions located inside the D4R units has been used to study the location of Ge atoms in the D4R units of Si,Ge,F-zeolites. First, the proposed methodology was validated in order to get a good correlation between experimental and calculated chemical shifts. Then the simulated signals are used to analyse the apparent controversial assignment that can be found in the literature.