In these pages crystal structures are visualised using Jmol, which allows the user the rotate and re-size the images using a mouse. Jmol is open source software whose applets run over the web. Your computer will need to have Java enabled to view the images.
The unit cell parameters of the crystal structures are based upon output from crystallographic databases. The Cambridge Structural Database is used for organic structures, and the Inorganic Crystal Structure Database, which is copyright by Fachinformationszentrum Karlsruhe (FIZ) in Germany, and the National Institute of Standards and Technology (NIST) in the USA, is used for inorganic structures.
The structures in these pages contain all the necessary information required for a Cambridge Pre-U course in Chemistry. There is also much besides. Where a structure is divided into basic and advanced pages, the latter go beyond what students are expected to know in the Pre-U course; these are intended to be interesting and challenging extension material.
The emphasis in these pages is on cubic structures, since these are the most symmetrical, and so it is through these that ideas of symmetry are most clearly demonstrated.
Please send suggestions of structures you would like to see, improvements, errors or general comments to Chas McCaw on cm520@cam.ac.uk.
Acknowledgements
The author would like to thank the following for making this project possible:
Dr Peter Wothers of the Chemistry Department at Cambridge for conceiving and backing the project, and for his continual support and many helpful suggestions.
Dr James Keeler of the Chemistry Department at Cambridge for introducing me to Jmol and for much back-up with the computing.
St Catharine's College, Cambridge for granting me a sabbatical position, accommodation, and for looking after me so well during the term.
The Department of Chemistry at Cambridge for providing me with an office and access to their excellent facilities; and to the Cambridge Crystallography Data Centre for their helpful cooperation.
Winchester College for granting me a sabbatical term.
Information on the minerals was taken from the Mineral Gallery at www.galleries.com.
Lists of structures conforming to the types described here were taken from A. F. Wells "Structural Inorganic Chemistry", 5th edition, F. C. Phillips "An Introduction to Crystallography" and the US Naval Research Laboratory's Center for Computational Materials Science (Crystal Lattice Structures) website at http://cst-www.nrl.navy.mil/lattice/.