University of Cambridge > Talks.cam > Engineering - Mechanics and Materials Seminar Series > Understanding zeolites through the structural mechanics of infinite frameworks

Understanding zeolites through the structural mechanics of infinite frameworks

Add to your list(s) Download to your calendar using vCal

If you have a question about this talk, please contact Ms Helen Gardner.

This talk has been canceled/deleted

Zeolites are microporous aluminosilicate minerals. A zeolite can be simply modelled as a set of vertex-pinned rigid tetrahedra: typically a silicon atom and four surrounding Oxygen atoms form a relatively stiff tetrahedron, with each Oxygen atom common to two tetrahedra. The Oxygen acts as a spherical joint, as the Si-O-Si bond angle is relatively flexible. The tetrahedra can be connected together in many different ways to give zeolites with various voids and channels, and this structure is essential to their important uses as molecular sieves and catalysts.

The interesting structural characteristic of zeolite frameworks is the equality between the number of rigid-body freedoms of the tetrahedra, and the number of constraints at the hinges. In fact this implies that there must be at least three inextensional deformation modes for the framework, and the presence of symmetry may increase this number. This insight may have relevance to understanding why there are a relatively small number of actual zeolites (around 200), compared with the several million hypothetical structures that have been found.

This talk is part of the Engineering - Mechanics and Materials Seminar Series series.

Tell a friend about this talk:

This talk is included in these lists:

This talk is not included in any other list

Note that ex-directory lists are not shown.

 

© 2006-2024 Talks.cam, University of Cambridge. Contact Us | Help and Documentation | Privacy and Publicity