Yesterday, I popped along to hear Roald Hoffmann (again) talking at his own birthday symposium. Also there was author and neurologist Oliver Sacks, who is not a chemist, but when I met him this morning was wearing a very natty periodic table t-shirt. It was in colour, much better than my white-on-red version. Note to self - update wardrobe.

Back to the facts. Roald Hoffmann got a Nobel prize for some very clever theoretical chemistry and some rules that explain, and can be used to predict, why and how reactions proceed. But his first published paper was actually on the thermochemistry of cement. Fascinating.

Oliver Sacks has not only a periodic table t-shirt, but he told me that for the past 60 years has carried a periodic table in his wallet as well. I don't think it has been the same one all that time, because it was in very good condition. And haven't they added umpteen elements in the past 60 years.