32 No. 6
Gadolin and the Cradle of the Rare Earths
A seemingly ordinary mine in the small village of Ytterby on Resarö Island, off the coast of Sweden near Stockholm, played a remarkable role in the discovery of the rare earth elements and the development of the periodic table. It was there that Carl Axel Arrhenius, a Swedish artillery officer with a penchant for mineralogy, found in 1787 a strange black dense mineral while prospecting for feldspar. A sample of ytterbite eventually reached Johan Gadolin (1760–1852), a professor of chemistry at the University of Turku in Finland, who reported in 1794 the presence of a new “earth” in the unusual mineral from Ytterby. Although Gadolin had actually isolated yttrium oxide (Y2O3), he is usually credited with the discovery of the element, which was subsequently obtained in fairly pure form by Friedrich Wöhler (1800–1882), better known of course for his synthesis of urea from ammonium cyanate. Three additional rare earth metals named after Ytterby (i.e., ytterbium, terbium, and erbium) were isolated in the decades following Gadolin’s seminal discovery, but it would be more than a century until the complete series of lanthanoid elements was uncovered.
The stamp illustrated herein was issued in Finland on 4 June 1960 to celebrate the bicentennial of Gadolin’s birth and features his likeness based on a portrait made when he was 19 years old, around the time he left his native Turku to pursue advanced studies at the University of Uppsala. In addition to the discovery of yttrium, Gadolin authored several books, including the first chemistry textbook published in Scandinavia, and pioneered the direct involvement of students in experimental work as part of their education. Not surprisingly, he received many academic honors and is usually considered the founder of Finnish chemistry. The element gadolinium, compounds of which are the most popular magnetic resonance imaging (MRI) contrast agents used today, was named after him.
Written by Daniel Rabinovich <[email protected]>.
last modified 22 November 2010.
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