Monday, October 11, 2010

Element of the Month: Praseodymium!

October's Element of the Month:


Atomic Mass: 140.908 amu
Melting Point: 935 °C
Boiling Point: 3520 °C

"Praseodymium" is a pretty fancy-pants name for a chemical element, especially one at the relatively low element number of 59. It is -- brace yourself -- yet another silvery colored metal, just like everything else, although it does oxidize easily, which often gives it a light green surface. It oxidizes so easily, in fact, that if you leave a chunk of it lying around in the open air, it will just turn into a pile of powdery greenish Praseodymium Oxide within a year, so like your mom always said, take good care of your Praseodymium. Don't leave it on the stove, either, as it burns at 150°C. Best is to store it in mineral oil until you need it, actually.

This stuff is pretty darn rare -- it's about as common as thorium, samarium, and gadolinium here on the Earth's crust -- and only occurs in minerals with other rare metalic elements. Because of this, it wasn't isolated until 1885, when it was collared by the immortal Baron Carl Auer von Welsbach, father of the modern cigarette lighter. It did not have a lot of obvious commercial applications, although it was found that you could use its oxides to dye glass a chartreuse color that could also be achieved through far cheaper means. That discovery didn't really go anywhere.

The Centerfold!

Modern applications are few in number and rather specialized. Like everything else, it gets thrown into alloys for aircraft engines. When alloyed with nickel, it somehow allows brainy science guys to generate low temperatures very close to absolute zero. The flint in your lighter -- thank you, Baron von Welsbach! -- is 4% Praseodymium, and it's used in ceramic dyes, to make things yellow, and in welder's goggles, where it filters out yellow light. And most interestingly, it's used in the arc lights used in movie lighting and projection, so it enhances our quality of life that way (depending on the movie, of course). You could live without it, though -- it is biologically inert as far as anyone can tell.

If you want to experiment with Praseodymium, be prepared to develop an intuitive sense of how hard it is to isolate. You're looking at around US$5000 per kilogram, roughly the price of really good saffron, choice Beluga caviar, or clandestine rhino horn. But only about a quarter of the price of good cocaine, apparently, although I find online information on this point to be shamefully disorganized.


gl. said...


Aviatrix said...

I never knew Pr was in cigarette lighters. Even cheapo ones in the impulse buy rack by the cashier at Canadian Tire?

Michael5000 said...

Aviatrix. ESPECIALLY those!