Friday, January 27, 2017

Element of the Month: Bismuth!

January's Element of the Month:


Atomic Mass: 208.98040 amu
Melting Point: 271.5 °C
Boiling Point: 1564 °C

"Bismuth" is such a homey, average-Joe name for an element! This always throws me off. It seems like it should be really low on the elemental table, and that it should be something that grandma keeps around the house for use as a dentifrice or to polish the silver or something. But in fact it's way down there at the bottom of the non-fakey elements, and even though it was known far enough back in history to have a non-sciency name -- something that doesn't end in "ium," basically -- it has never been especially important or useful to the human community. Indeed, we humans have mostly regarded it as an impurity to be reckoned with in our lead mining. Its marginal status turns out to be inherent in the name, which is either from the Arabic, meaning "kinda like Antimony," or possibly from the German, meaning "that white stuff."

In visual catalogs of the Elements, Bismuth is always over-represented because pure Bismuth can be coaxed into crazy technicolor crystals. But I know that you wouldn't want me to pander, so I'm going to show you a proper image of metallic Bismuth. It is of course a silvery grey metal.

The Centerfold!

After all, we're scientists here. There's no point in confusing the issue by gawping at garish images of Bismuth crystals as if they were an important aspect of its chemistry or use! I think we are above that kind of crass element pornography.

Whoopsie, how did those slip in?

Well anyway, with an elemental number up in the 80s, you are probably thinking two things. First, "wow, this stuff must be heavier than Lead!" That's kind of true! Lead is Element #82, Bismuth is Element #83, so on an atom-for-atom basis Bismuth is the heavier one. On the other hand, Bismuth is a bit less dense than Lead in solid form, so it's not quite as heavy volume-for-volume. They're close enough, though, which is why Bismuth is sometimes used these days for stuff like buckshot and fishing weights, where you just need a heavy substance and don't want to introduce lead toxicity into your friendly local ecosystem.

The other thing you are probably wondering is "hey, is it radioactive?" Great question! Bismuth was thought by our primitive 20th century forebears not to be radioactive, but we moderns have looked into the matter and determined that they were wrong! It emits alpha radiation, and has a half-life of 19,000,000,000,000,000,000 years! So... you know what, let's round off our figures and say "we were right before, it's not really radioactive."

Incidentally, I was kind of right about Bismuth being something that grandma might keep around the house for practical use. In a flash of insight, I looked up "Pepto-Bismol," and boom: the active ingredient in that popular antacid is Bismuth subsalicylate, AKA "pink Bismuth." Says here that Pepto-Bismol was originally a drug sold directly to doctors for use in treating infant cholera. It seems to work, but nobody really knows why.

I hope you enjoyed these very sciency facts about Bismuth.

1 comment:

mrs.5000 said...

Gawp! The crystals at last photo especially would make a lovely roof structure--perhaps for a Mayan tumulus? Just turn it upside down, it would be all silvery gray rock outside and iridescent corbels on the ceiling. No problem to scale it up, right?