March's Element of the Month: Cobalt!

March's Element of the Month:Cobalt!
Co
27

Atomic Mass: 58.94 amu
Melting Point: not sure
Boiling Point: not sure

March’s Element of the Month is Cobalt! Now, usually I am able to use the resources of the so-called “World Wide Web” to synthesize the state of knowledge about any given monthly element, but since I am writing today from a telecommunications-free cabin overlooking a sullen, stormy, wine-dark sea, we’ll have to work from what resources are at hand -- to wit: Volume 3 of the 1921 World Book (“Child Study to Electrode”) and Volume 5 of the 1959 Encyclopedia Britannica (“Castir to Cole”).

So, let’s see. From the former, we mostly learn that Cobalt is a silver-white metal that's an awful lot like Nickel, and like Nickel is good for coating other metals so they stay nice and shiny and don’t corrode. Except, it’s more expensive than Nickel, so who needs it. Also, you can make a pink ink out of Cobalt Chloride and, if you write on a piece of pink paper, it’s invisible – until you heat the paper, when the writing turns blue! Cool. And then of course Cobalt compounds are used in pigments for paints, dyes, glazes, and what-not. How important is Cobalt? Well, the town of Cobalt, Ontario is given as the world center for its production, and the population as of 1916 is listed as 5500 and dropping. Draw your own conclusions.

The Centerfold!

The Britannica tells us that the word Cobalt comes from a 14th Century German word for evil spirits, the connection being not only that Cobalt is often associated with Arsenic, which was of course a major health hazard for miners, but also that it was absolutely useless, a waste of mining time and energy. So historically, Cobalt seems to be the whipping boy of the periodic table, getting no love from anybody. The venerable encyclopedia does eventually concede, though, that the uses of cobalt “are not numerous, but are increasing.” Being strongly magnetic, it has new applications in the bleeding-edge technology of “telephony,” and its alloys are being used in heating elements and high-speed cutting tools.

The Britannica devotes a stultifying three columns to the chemical properties of Cobalt, going out on a limb with this daring summary statement: “The chemistry of cobalt shows many resemblances to, as well as differences from, the chemistry of iron and nickel, its neighbours in the periodic system.” It also notes that “finely divided metallic cobalt occludes as much as 100 times its volume of hydrogen, and readily gives it up again when heated to 200C in vacuo.” I only vaguely understand what that means, but it sounds pretty cool, and also I will be looking for any further opportunities to use the phrase in vacuo.

Want more Cobalt in your life? You might have to look hard: it represents only 0.000018% of the matter here on the crust of the Blue Planet [[July 2012 update: This figure seems a couple of order of magnitude too low, compared with contemporary sources]]. For a shortcut, though find yourself a meteorite. You might find that it’s as much as 2.5% Cobalt!

Incidentally: Best compare-and-contrast of articles between Volume 3 of the 1921 World Book and Volume 5 of the 1959 Encyclopedia Britannica? “Churchill, Winston.” They are SO inconsistent!