Dear All
You are cordially invited to a talk to be given by Robin Hendry from Durham University, UK. Hendry is author of a forthcoming book, The Metaphysics of Chemistry and numerous articles on the philosophy of chemistry. When: 11.00 am, Tuesday, 14 December. Location: Chemistry Building, Lecture Theatre 4. The Metaphysics of Molecular Structure Robin Findlay Hendry Department of Philosophy Durham University Molecular structure is a central notion in chemistry: a substance's molecular structure provides the explanation for its chemical and spectroscopic behaviour, and IUPAC makes it the basis of chemical nomenclature and classification. Some philosophers see this as the basis for an argument that structure is essential, in that it makes a chemical substance what it is. But what is a molecular structure? I begin by investigating the historical roots of structure in nineteenth-century organic chemistry, when it was already a topological, rather than merely a geometrical, notion: a structure was not a set of atoms in relative positions, but a network of atoms connected by bonds. So what is a bond? The advent of quantum-mechanical explanations of chemical bonding caused some chemists to doubt the physical basis of the bond. Quantum mechanics rules out the existence of anything quite like G.N. Lewis' electron-pair bond. As Charles Coulson put it 'in the beautiful density diagrams of today the simple bond has got lost.' There are two kinds of response to this situation. One is to regard the classical chemical bond as no more than a theoretical tool. It was useful in the nineteenth century, and may even remain so today, but it has no basis in physical reality. Perhaps there are no such things as bonds: there is only the phenomenon of bonding, which ultimately finds its explanation in energy changes. But doesn't the explanatory indispensability (and ubiquity) of the bond suggest that it should not be dispensed with entirely? The second response therefore attempts to salvage something of the classical bond. I conclude by critically examining Richard Bader's Quantum Theory of Atoms in Molecules as a way of locating the bond in quantum-mechanical reality. Debbie Castle | Administration Assistant Unit for History and Philosophy of Science Faculty of Science THE UNIVERSITY OF SYDNEY Rm No. 441 Carslaw Building, F07 | The University of Sydney | NSW | 2006 T +61 2 9351 4226| F +61 2 9351 4846 | e [email protected] <mailto:[email protected]> | W http://sydney.edu.au/hps <http://sydney.edu.au/hps> Office Hours: 9am - 4.30pm: Monday, Tuesday & Wednesday CRICOS 00026A This email plus any attachments to it are confidential. Any unauthorised use is strictly prohibited. If you receive this email in error, please delete it and any attachments. Please think of our environment and only print this e-mail if necessary.
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