Imagine If You Will, Another Dimension of Atoms...

Cobalt and nickel are elements 27 and 28, respectively, but this wasn't always so. Older textbooks often put cobalt and nickel together because they weren't sure which came first. Though there were chemical reasons to believe that cobalt preceded nickel in the Periodic Table, no matter how carefully they measured it, nickel always came out lighter than cobalt, even though it should be heavier.

Scores of new elements were discovered in the 19th century and back then weight measurements were used to identify them and to place them in the table. T. W. Richards won the Chemistry Nobel in 1914 "in recognition of his exact determinations of the atomic weights of a large number of the chemical elements." But realize that while the Periodic Table originally sorted and arranged chemical elements according to their atomic weights, the table actually sorts the elements according to their atomic numbers. The notion of atomic number was unknown to 19th century chemists.

A hypothetical sample of cobalt, nickel, and copper** ions would give a mass spectrum looking something like this:

Natural cobalt is monoisotopic (⁵⁹Co), while nickel has five isotopes: ⁵⁸Ni, ⁶⁰Ni, ⁶¹Ni, ⁶²Ni, and ⁶⁴Ni, with the lightest being the most abundant. Note how ⁵⁸Ni precedes ⁵⁹Co.  Why cobalt likes neutrons more than nickel does is an interesting question for which I have no answer.

Henry Moseley first showed that cobalt and nickel were correctly ordered despite their anomalous weights. Around the same time, J.J. Thompson invented mass spectrometry which sorts ions according to mass as shown above. Thompson discovered that neon had two isotopes but the concept of isotopes wasn't fully understood until James Chadwick discovered the neutron in 1932.  Chadwick's discovery also enabled the subsequent syntheses of elements beyond uranium.
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*Tellurium (element 52) presents a similar weight anomaly because it is on average heavier than iodine (element 53).
**I wrote about copper isotopes back here and included it because it falls close to Ni and Co.

La Mirella Mia

While on the topic of cobalt, I remembered my early fascination for another thing cobalt: the Campagnolo Gruppo Cobalto. If you don't know, Campagnolo SPA is the the name of an Italian high end bicycle component manufacturer. Campagnolo (Campy) parts dominated the high-end bike component markets for years until the Japanese moved in on them, offering more for less. But Campagnolo still led in form plus function.  Here is a photo of the Cobalto brake set I coveted but never owned.

In 1979, I bought a 10 speed bicycle called a Mirella. Here's a link showing what one used to look like.  Mine was gold and not blue. Same chrome lugs. Mafac brakes. I rode that bike 15 miles a day, weather permitting, commuting back and forth to campus. I also rode it around Dane County and around the lakes on weekends.

I crashed the bike once on University Avenue going over some railroad tracks. The front wheel came loose and I planted the fork in the asphalt. I cracked my forearm in the fall but managed to carry the bike back to State St. where I worked before seeking medical attention for myself (the bike was more important to me). The guys at the old Yellow Jersey Coop on State St. were able to straighten the fork for me and a month or so later I was at it again, biking all over Dane County.

Years later I had the original paint stripped and added braze-on fittings for the front derailleur, water bottle cages, and brake line guides across the top tube. I had it painted a bright Italian red. I also upgraded the components with Campy Super Record brakes and a gorgeous Campy Chorus aluminum crank (I still have the original three-pin Campy crank made of chrome-plated steel. I tried to sell it once on eBay but no takers). I also added front and rear Chorus derailliers. And a Cinelli stem. The only thing original (besides the frame) left on it are the high flange Campy hubs and the drop-outs which are part of the frame and thus non-negotiable.

Somebody vandalized my Mirella in Denver. They took the Campy Record quick release skewers, the Super Record brakes, and they were working on taking the seat post. Bastards. I suspected someone in the apartment building because the bike was in a security locked basement at the time.

Here's photo of it now, stowed up in the rafters in the garage. It still works fine:

THIS BIKE IS NOT FOR SALE

Real 10 speeds are so 70's.

Cobalt, Goblins And Globins

Cobalt's mysterious name apparently traces back to Greek and Latin roots meaning evil spirit. read more. Though known to Paracelsus (1493-1541) as salts and oxides, cobalt was not considered an element until Antoine Lavoisier redefined the very term "element."
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Chemists have a little mnemonic teaching rhyme which goes:

 If it's blue, it's cobalt (II).

Cobalt (II) salts give the gorgeous deep blue color which contrasts the stark white tin glaze used in Delftware pottery:

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Like iron, our bodies need cobalt -- just less of it. Vitamin B₁₂, also called cobalamin, contains cobalt. Vitamin B₁₂ fascinates me because it was present at several very important 20^th century chemical mileposts. I could write a blog post about each and every of the following:

• How the discovery of liver juice and liver extracts cured pernicious anemia, leading to a Nobel Prize in Medicine in 1934.
• How after the curative factor was isolated and named Vitamin B₁₂, British chemist Dorothy Hodgkin determined its structure using X-ray crystallography. Vitamin B₁₂ was then the most complex natural molecule known.* Hodgkin received the 1964 Nobel Chemistry Prize for her work.
• How Hodgkin's structure inspired Robert Burns Woodward, American chemist extraordinaire, to synthesize B₁₂ de novo. This work, his crowning oeuvre, in collaboration with Albert Eschenmoser in Switzerland, spanned a dozen years and spawned much new chemistry and also a set of rules which led to another Nobel Prize in 1981 (which Woodward would have shared had he lived).
• How the isolation of Vitamin B₁₂ sparked a legal battle in the patent world beginning in the late 1950's: the legal question was whether something found in nature was patentable subject matter or not. Ironically, SCOTUS may be revisiting parts of a 1958 case this fall when they decide to hear arguments or not regarding the patentability of genes.

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*While the contemporaneous discovery of DNA (the double helix) was perhaps more important, B₁₂ was intellectually more interesting, involving as it did a novel cobalt-carbon bond.