Friday, March 13, 2015

Element of the Month: Mercury!

March's Element of the Month:


Atomic Mass: 200.592 amu
Melting Point: −38.8290 °C
Boiling Point: 356.73 °C

In fifth grade, some of the guys in my class got hold of some liquid metal. It was pretty cool, and we all tried to bum a chance to mess with the stuff at recess. It was Mercury, of course, although I think we might have been calling it "quicksilver." I don't remember whether Mr. Smith ever found out about it, but either the stash eventually diminished down to nothing -- the stuff doesn't stay put very well -- or some grownup cottoned to the fact that we were playing with what the Norwegian Minister of Environment and Development would many years in the future call "among the most dangerous environmental toxins," and ruined the fun. Well, that's childhood for you.

Mercury is an Element of mystery, the first being "woah... how can, like, a metal... be a liquid...?" It is certainly counter-intuitive, as we are used to metals in general being pretty damn firm and resilient. But on the other hand, we also know that any metal can become a liquid if we heat it up enough; it just so happens that Mercury has a very low melting point indeed. If we cooled things down to that magical point where Fahrenheit and Centigrade converge, negative forty degrees, Mercury would act a lot more like what we're used to from the other metals. You could, for instance, beat someone up with a length of Mercury pipe. Then you could go back indoors and let the pipe melt away at room temperature; when the police came, you would say "I don't know what he's talking about, but I certainly don't have any metal pipe here. Go ahead and search the place!" The possibilities are endless.

A smart reader like yourself might say "OK, sure, it has a low melting point, but why does it have a low melting point?" The answer apparently has to do with the way the electrons are configured within the various electron shells. If you want to go any deeper than that, I suggest you consult someone with a real understanding of chemistry. Or maybe physics. Probably both.

The Centerfold!
Mercury in some guy's hand, even though he was not in
my fifth grade class and should probably know better.

Another mystery of Mercury: why is its Chemical symbol "Hg"? Well! Says here that the Greek ὑδράργυρος, meaning "water-silver," was Latinized as "hydragyrum." So, why aren't we calling the soupiest metal "Hydragyrum" anymore? I'm not sure. The majority opinion seems to hold that Mercury was named after the Roman god, by analogy with his habit of flitting here and there and being difficult to pin down. However, I also note that Mercury is one of the seven Elements that were associated with planets, or "planets":
  • The Sun - Gold
  • The Moon - Silver
  • Mercury - Mercury
  • Venus - Copper
  • Mars - Iron
  • Jupiter - Tin
  • Saturn - Lead
Since there were perfectly obvious alternative names for Element #80 around, like "Hydragyrum" and quicksilver, it seems more likely to me that the Element gradually acquired the name of the planet it was associated with, rather than being named directly for the god. It's a bit academic anyway, I suppose, since the planet was named for the god.

Mercury has been used for, heavens, just about everything. Famously, it was used to block hats, and the symptoms of the resultant Mercury poisoning is the source of our phrase "mad as a hatter." Mercury and Mercury Chloride were widely used into the 20th century to treat constipation, worms, and syphilis. It probably worked pretty well for the first two. It didn't really work at all for syphilis, however, but since the symptoms of Mercury poisoning and syphilis are fairly similar, you can imagine that physicians could have confused the hell out of themselves trying to get the dosing right. If you read about "the blue pill" in a historical novel? That's Mercury.

Most applications of mercury, from thermometers to batteries to chlorine production to mascara, have been steadily phased out over the past several decades. Fluorescent lighting, however, is all about the excitation of Mercury vapor. Fluorescent lights are much more energy efficient than their incandescent brethren, so we've all been sternly admonished to switch over to the more toxic Mercury-heavy bulbs. Is this a wise trade-off? I don't know!

That's probably enough about Mercury for now.

Alexander Calder (2-2, .508, exited Tournament October 2014)
designed "the Mercury Fountain" for the 1937 Paris Expo.


mrs.5000 said...

I'm still trying to wrap my head around mercury getting its name BECAUSE it was mercurial...that's like, whoa, trippy...

Michael5000 said...

See, one thing I read said that the word "mercurial" comes from the god -- dashing around all over the place, like he did. But that feels SO WRONG to me, since for me the essence of the word "mercurial" is moving around, metaphorically, like the Element Mercury.