31. Gallium: Caught Wet-Handed

Meet one of the periodic table’s lesser-known liquid metals — and beware some dangerous competition from a few felonious element collectors.

Featured above: A certain 19th-century French chemist who may have been a little bit cocky.

Show Notes

This episode’s alternate title was, “The Wet Bandits.”

Credit Kean: The gallium gag is such a classic chemistry prank that author Sam Kean named his seminal book of elemental history, “The Disappearing Spoon.” It’s an excellent book, and I go out of my way to make sure these podcast episodes don’t just reiterate what he’s already documented.

I Thought There Were More Fools On The Internet: Here are a couple videos that demonstrate gallium’s “wetness” and mercury’s “dryness.”

Videos of mercury are shockingly uncommon on YouTube, but this is one where you can see how the metal acts when prodded with a glass instrument.

Creating that mirror is only possible because gallium adheres to the glass, i.e., it wets it.

But that’s actually an additional complication when it comes to the thermometers. By wetting the glass, the galinstan won’t rise and fall to accurately report the temperature. The interior needs to be coated with Teflon, or be made of gallium nitride, to ensure the thermometer will work. It’s a lot of effort to go through, but worth it to make sure kids don’t wind up mad as a hatter.

Be Prepared: The engineer and technician who saved the day at the SAGE facility might have been particularly vigilant because the facility had been hounded by the Russian government for months. They’d threatened to requisition the valuable metal to hand it over to the defense department. Is this connected to the attempted heist? Who can say?

But the gallium was already prized by sticky-fingered scientists. Earlier in the 90s, a small but noticeable amount of the metal “went missing” when scientists with few scruples started siphoning it off after hours. That actually wound up skewing some experiment results, and a few people did wind up in jail for that escapade.

Wrecka-Aluminum: When Mendeleev predicted the existence of gallium, he referred to it as “eka-aluminum,” borrowing a Sanskrit prefix to indicate that it was one order higher than aluminum on his periodic table. (i.e., gallium is directly below aluminum.)

Coincidentally, molten gallium will combine with aluminum to make it fantastically brittle. It’s quite a sight to see… so that means, naturally, more video:

I was kind of hoping to find a video of someone pouring gallium on a full can of soda, maybe after shaking it up a whole bunch. But I suppose the only people who use the internet are reasonable and risk-averse.

Click To Read Transcript

Sources

  1. The Annals Of Chemistry, About A New Metal, Gallium. P.E. Lecoq de Boisbaudran, 1887.
  2. Elementymology & Elements Multidict, Gallium. Peter van der Krogt, 1999 – 2010.
  3. The Verge, Gallium Nitride Is The Silicon Of The Future. Angela Chen, November 1, 2018.
  4. Please!
  5. Spaceship Neutrino, p. 170. Christine Sutton, 1992.
  6. Measurement Of The Solar Neutrino Capture Rate With Gallium Metal, April 29, 1999.
  7. Science, Thieves Bedevil U.S.-Russian Neutrino Detector. Science News Staff, November 12, 1997.
  8. Science, Thieves Target 60-Ton Neutrino Detector. Andrew Allakhverdov, Vladimir Pokrovsky, November 14, 1997. Unfortunately, this paper requires login credentials to read, and I’m not able to find a more public source.
  9. The New York Times, A Detector’s Rare Metal Faces Seizure In Russia. Malcolm W. Browne, January 20, 1998.
  10. Breaking Defense, The Biggest Thing Since Silicon: Raytheon’s Gallium Nitride Breakthrough. Sydney J. Freedberg, Jr., February 20, 2015.

2 Replies to “31. Gallium: Caught Wet-Handed”

    1. Five points! 🙂 And as I’m sure you know, that’s why tin’s chemical symbol is Sn. (As we mentioned in the Titanium episode, TiN is titanium nitride. It all makes complete sense and isn’t confusing at all.)

      Thanks for commenting!

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