Dresden 2009 – wissenschaftliches Programm
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MM: Fachverband Metall- und Materialphysik
MM 35: Poster Session II
MM 35.42: Poster
Mittwoch, 25. März 2009, 16:30–18:30, P4
Physical significance of the flexibility window in zeolites — •Asel Sartbaeva1 and Stephen Wells2 — 1Inorganic Chemistry laboratory, South Parks Road, Oxford OX1 3QR, UK — 2Department of Physics and Center for Scientific Computing, University of Warwick, Coventry CV4 7AL, UK
We have recently noted that aluminosilicate zeolite frameworks, modelled as a periodic system of corner-linked polyhedra, display a range of densities within which the polyhedra can in principle be made geometrically ideal. Outside this range, distortions are inevitable due to either stretching of bonds or collisions between oxygen atoms on adjacent tetrahedra. The densities of high-silica zeolites at room conditions is found to lie at the low-density edge of the window, indicating that zeolites are maximally expanded structures. We present new evidence, from a theoretical/experimental study of zeolites with ANA topology, that the flexibility window is a valuable guide in explaining the structures and structural phase transitions of zeolites.