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Comment by jazoom

7 years ago

It's not unique in that. There are other single-atom molecules.

I don’t know anything about chemistry beyond high school (US public school) but presumably helium is the smallest single-atom molecule you’ll encounter if hydrogen is off the table.

TIL, which others? I thought other noble cases are dimers like Xenon also unlike helium I think all of them now found to form some compounds especially with the fluoride family.

  • All noble gases exist as monoatomic elements.

    They don't form compounds easily but there exist molecules containing at least xenon, radon. Even helium can be made to participate in reactions if pressure is high enough.

    • You only tend to get a noble gas reacting with something if you approach the arena of irresistible force (fluorine) meets unmovable object (xenon), and get Xenon Tetrafluoride. https://en.wikipedia.org/wiki/Xenon_tetrafluoride

      The noble gases have complete electron shells and are quite satisfied with themselves, not needing any bonds with anything else. However, the larger the atom, the more flexibility it has with how many electrons it can hide down the back of the sofa. Xenon is the largest non-radioactive noble gas, so it was the first to have a noble gas compound discovered. Fluorine is just desperate to acquire an electron to complete its electron shell, and will do it by whatever dirty tricks it can manage, which is why it is able to wrest one from Xenon's tight grasp.

      https://en.wikipedia.org/wiki/Noble_gas_compound

      This sort of thing (along with Derek Lowe's blog) makes chemistry interesting for me.

      2 replies →

Im guessing it's the only one that's gaseous at room temperature and pressure?

Edit: Never mind, all the nobel gasses.