Footnote of the Month: January 2011
What are the “minor metals,” so-called? They are metals not traded on the London Metal Exchange, but they nonetheless have a wide range of uses essential to modern life. Some of them fall into a category called the rare earth elements–which are not especially rare, but were very difficult for early chemists to separate. No fewer than four of these are named after the tiny village of Ytterby, Sweden, where they were first discovered: yttrium, terbium, erbium, and ytterbium. The other minor metals have lovely names, too: antimony, arsenic, beryllium, bismuth, cadmium, calcium, cerium, chromium, cobalt . . . and on through tantalum, tellurium, titanium, tungsten, vanadium, and zirconium. Tom Lehrer, anyone?
In Uncle Tungsten, Dr. Sacks talks about his first encounters with the rare earths.
I think I first heard of the rare earths from my mother, who was a chain smoker and lit cigarette after cigarette with a small Ronson lighter. She showed me the “flint” one day, pulling it out, and said it was not really flint, but a metal that produced sparks when it was scratched. This “mischmetal”—cerium mostly—was a mishmash of half a dozen different metals, all of them very similar, all of them rare earths. This odd name, the rare earths, had a mythical or fairy-tale sound to it, and I imagined the rare earths as not only rare and precious, but as having special, secret qualities possessed by nothing else.
Later Uncle Dave told me of the extraordinary difficulty which chemists had had in separating the individual rare earths—there were a dozen or more—for they were astoundingly similar, at times indistinguishable in their physical and chemical properties. Their ores (which for some reason all seemed to come from Sweden) never contained a single rare-earth element, but a whole cluster of them, as if nature herself had trouble distinguishing them. Their analysis formed a whole saga in chemical history, a saga of passionate research (and frequently frustration) in the hundred years or more it took to identify them.
from Uncle Tungsten, Knopf edition, p. 207.