Molecules: You'd better learn to live with them.
Tin is a nice enough metal, strong and nontoxic enough that for some time we made food-grade cans and foil using it in part. It has a darker side, however: tin pest.
Below a relatively high temperature (ca 13C/55F), "white tin" can convert to a different, more brittle phase, "grey tin." This is called tin pest. Tin, stored cold, will crumble.
Cruelly, such processes are autocatalytic and are difficult to stop once they start (save storing your tin at more friendly temperatures). As the wikipedia article notes, tin pest killed North Pole explorers, Napoleon's men, and destroyed church organs.
Nowadays we understand alloys a little better, and simply putting in a little other metal seems to help.
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Comments
The book Napoleon's Buttons: How 17 Molecules Changed History by Penny LeCouteur and Jay Burreson has a chapter on the role of tin pest in Napoleon's failed campaign against Russia.
Posted by: Rosie Redfield | October 1, 2007 9:44 PM
...such processes are autocatalytic and are difficult to start once they stop...
Shouldn't that be difficult to stop once they start? :-)
Posted by: Michael Zappe | October 1, 2007 11:24 PM
From what I understand, the role of the tin buttons in Napoleon's failed campaign has been overstated. The connection is dubious at best. But, it does make a great story.
The LeCouteur and Burreson book is great. It's required reading in my organic class.
Posted by: Chemgeek | October 2, 2007 9:46 AM
Reagent tin (white, metallic) is available as brittle rods. Put a section in a sealed vial in your freezer. All looks OK for about a month, then... Grey tin has a lower density. The rod progressively shatters to dust after nucleation.
Diamond seeds similarly. Transition activation energy is hard by the total lattice energy. It's good to ~1000 C in air or ~1500 C in neutral or reducing atmospheres. Graphite is much less dense. One the transition starts at a surface defect it is almost explosive througout the bulk.
Posted by: Uncle Al | October 2, 2007 10:54 AM
Best tagline ever.
Posted by: Adam Engelhart | October 3, 2007 12:08 AM
So one thing about tin you don't mention is it's insanely powerful and annoying stench. As the metal the smell is noticable, (same as lead) but as an organotin reagent (alkyl or aryl tin chlorides) this smell is powerful enough to banish many people from the room for an hour or so.
I suspect, however, at least part of the reason you don't mention it is due the the highly variable ability of people to smell tin. I can tell if someone is running a Stille from miles away, and i won't use the Isco or Biotage that purified that reaction for weeks. Most of my coworkers, however, have no idea that tin has a smell.
So informal poll time: Who here can smell tin?
Posted by: Yttrai | October 4, 2007 3:32 PM
Another tin problem: Tin Whiskers
Wikipedia: http://en.wikipedia.org/wiki/Tin_whiskers
Tin will form whiskers which can short out electronics. This can be substantially reduced by alloying with lead. However, as Europe is banning lead in electronics, it will likely become a major problem again. See http://www.physorg.com/news110812295.html
Posted by: Jim | October 6, 2007 5:06 AM