There is a web page at the University of Sheffield, England, with a clickable periodic table. I've used it a number of times, and I think it's pretty good. It is: http://www.shef.ac.uk/~chem/web-elements/ Steve Alford Radiation Safety Officer Dana-Farber Cancer Institute Boston, MA 02115 (617)632-3005 steven_alford@dfci.harvard.edu