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Updated: Jul 18, 2026
Synthesis of Zeolites Using the ADOR (Assembly-Disassembly-Organization-Reassembly) Route
Published on: April 3, 2016
Computational study of location and role of fluoride in zeolite structures
Angeles Pulido1, Avelino Corma, German Sastre
1Instituto de Tecnologia Quimica, UPV-CSIC, Universidad Politecnica de Valencia, Avenida Los Naranjos s/n, 46022 Valencia, Spain.
Abstract:
The distribution of fluoride ions has been studied in the pure silica IFR, ITH, IWR, STF and STT zeolite structures using computational techniques. The interactions between the F- and SDA+ ions (where SDA is the organic structure directing agent) are able to explain the F- cage occupation found experimentally. While studying the short-range fluoride-framework interactions, a relationship was found between the Si atoms forming the pentacoordinated units and the lowest F- defect energies, which rationalizes the experimental Si-F bonding in terms of energetic stability. It is proposed that the F- location is governed by a two step process. In a first stage, the electrostatic long-range forces and, especially, the interactions between the F- and the SDA+ ions, decide which cage will be filled with F-; in a second stage, once the F- cage location is decided, the F- forms a covalent bond with a Si site to form an energetically stable pentacoordinated unit [SiO4/2F]-.
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