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RESEARCH PRODUCT
Net charge and polarizability of zeolitic Brønsted acidic sites
G. CastellanoFrancisco Torrenssubject
biologyChemistryInorganic chemistryActive siteMicroporous materialCondensed Matter PhysicsAtomic and Molecular Physics and OpticsSilanolchemistry.chemical_compoundPolarizabilitybiology.proteinPhysical chemistryPhysical and Theoretical ChemistryPolarization (electrochemistry)Weak baseZeoliteBrønsted–Lowry acid–base theorydescription
The interacting induced-dipoles polarization model, implemented in our program POLAR, is used for the calculation of the effective polarizability of the zeolitic bridged OH group, which results much higher than that of the free silanol group. A high polarizability is also calculated for the bridged OH group with a Si4+, in the absence of Lewis-acid promotion of silanol by Al3+. The crystal polarizability is estimated from the Clausius-Mossotti relationship. Siliceous zeolites are low-permittivity isolators. The interaction of a weak base with the zeolitic OH can be considered as a local bond. Only when cations are located in the zeolite micropore, next to tetrahedra that contain trivalent cations, are large electrostatic fields generated. They are short ranged, and the positive cation charges are compensated. © 2007 Wiley Periodicals, Inc. Int J Quantum Chem, 2007
| year | journal | country | edition | language |
|---|---|---|---|---|
| 2007-01-01 | International Journal of Quantum Chemistry |