Friday, October 26, 2012

Element of the Month: Gallium!

October's Element of the Month:


Atomic Mass: 69.723 amu
Melting Point: 29.7646 °C
Boiling Point: 2204 °C

Gallium is the lowest-numbered element that you don’t know a damned thing about. Well, except maybe Beryllium and Vanadium. Check it out: Element #26, Iron. Element #27, Cobalt. Element #28, Nickel. Element #29, Copper. Element #30, Zinc. Element #31, Gallium. On the periodic table, Gallium is the gateway to the unknown; there will still be a few familiar landmarks in the 30s (Arsenic), 40s (Silver), and 50s (Tin, Iodine), but they are scattered among all sorts of other esoteric Elements that you would never have heard of if you were not such an avid IAT enthusiast.

If I’m wrong, and you do know a damned thing about Gallium, you probably know it mostly for its curious physical properties. For instance, check out its melting point. Low, ain’t it! 29.7646 °C! That means that it is probably solid at room temperature, assuming that your room has good climate control. It melts in your hands, though, and certainly in your mouth, although the later experiment is not particularly recommended. Also, it is one of only a very few substances that increases in size as it freezes. In the case of water, this peculiar property makes life possible on our planet; but in the case of Gallium, it’s not such a big deal. It does, however, make it a bad idea to pour liquid Gallium into a rigid container and then leave it to set. Like ice cube trays, a Gallium container needs a little “give.”

The Centerfold!

Gallium is not without a certain appeal.

It seems like almost every metallic element we talk about is used in alloys with steel and other structural materials to add strength and durability. But since Gallium has the melting point of butter, it’s obviously not going to see much application in high-performance jet engines. It also reacts easily with both alkalis and acids, another excellent reason to keep it out of your alloys. It is so reactive, in fact, that it doesn’t exist in a pure or even a very concentrated form in nature. There’s a scattering of molecules here, there, and everywhere, but no nuggets, veins, or seams of the stuff; they all would have reacted away in the dim geological past. When humans want some, they are usually able to isolate it by sifting diligently through the leavings of aluminum smelting. A few of its compounds are handy as filaments in LEDs (or whatever – I don’t know if the glowy bit in an LED is technically a "filament"), and also in some esoteric way in the manufacture of certain kinds of electronic components. It is not, shall we say, one of the strategic minerals that people get all worked up about.

The endlessly clever Mendeleev looked hard at his spreadsheet of the elements and predicted that there ought to be another substance kind of like aluminum in the world, and it was only four years later that the also very clever Paul-Emile Lecoq de Boisbaudran was able to produce the stuff. Lecoq de Boisbaudran would go on to discover Samarium, Dysprosium, and Europium, but Gallium would always be special to him; not only was it his first element, but its discovery was an important early confirmation of Mendeleev’s whole setup. He named it Gallium to honor France (Gaul) or very possibly just to honor himself: Gallus is Latin for “rooster,” which is English for “(le) coq.” Personally, I feel that Boisbaudranium would also be a good elemental name, and hereby refer it to the IUPAC/IUPAP Transfermium Working Group for consideration next time a new fakey element comes down the pike.


mrs.5000 said...


Please tell us, Dr.Science5000, how does the fact that water expands when it freezes make life possible on this planet? By...what on earth...turning rocks into dirt?

PB said...

A very small correction, and one that certainly doesn't change the point, but the Latin for rooster is gallus; Gallia is the province of Gaul, which is of course modern-day France.

Michael5000 said...

Corrected accordingly! And three Dorkfest points for the Latin catch!

Morgan said...

If you don't mind Dr. Science5000, I'll answer Mrs. 5000's question.

The fact that water expands - or, more accurately, crystallizes in a less packed form than it is when it is liquid - is important because the density of ice is less than the density of water. Therefore, ice floats. In the oceans, when it is cold enough for water to freeze, the ice that is formed floats to the surface, allowing it to cool. If ice were denser than water, it would sink to the bottom of the ocean and spread its low temperature to more water, causing the ice to spread drastically and lower the temperature of the oceans to near or below freezing and most points. Those conditions would not be too friendly to life.

Chuckdaddy said...

How many dork points did Morgan just get? That was an awesome explanation.

Michael5000 said...

Secondarily, water's ability to flow into and among rocks, then expand inexorably once frozen, is 99% of what grinds solid rock down into sand, silt, and clay particles that can be components of soil, which is required by anything that packs roots, stems, and leaves.

But yes, ice's willingness to float and insulate the sea, rather than to sink, spread, and freeze it solid, is what really keeps the fundamentals of life kicking.

gl. said...

I think that's the sexiest "Element of the Month" centerfold we've seen so far. oh, my goodness! *fans self*