Johan Gadolin was born in Åbo in today’s Finland on June 5, 1760. The city belonged to Sweden at the time; its Finnish name is Turku. He first studied mathematics and physics at the Royal Academy in Åbo and later switched to chemistry. In 1779, he continued his studies at the University of Uppsala, Sweden, under the supervision of Torbern Olof Bergman.

In 1781, Gadolin finished his dissertation on the analysis of iron. He left Uppsala and returned to his hometown Åbo, where he first served as Extraordinary Professor at the Royal Academy. He was appointed Ordinary Professor of Chemistry in 1797 and remained there until his retirement in 1822.

Johan Gadolin’s contributed to physical, analytical, and inorganic chemistry, but he is most famous for his discovery of the first rare-earth compounds. In 1792, he received a sample of a black mineral from a quarry in the Swedish village Ytterby. Careful analysis over the course of two years led him to the conclusion that besides aluminum oxide, iron oxide, and silicic acid, the mineral contained roughly 38 % of a previously unknown compound.

The mineral was called ytterbite (later renamed gadolinite in Gadolin’s honor). The unknown compound was called yttria and later determined to contain yttrium oxide. This discovery was the first of many, and by 1878, four rare-earth elements had been found in the same mineral and named after the village near the quarry: yttrium, erbium, terbium, and ytterbium.

Gadolin greatly influenced chemistry in Finland and was one of the first chemists to demand the students perform laboratory exercises. He also wrote the first Swedish-language textbook that questioned phlogiston theory (the theory that a substance called “phlogiston” is contained in combustible materials and released during burning). He was knighted three times for his achievements. Johan Gadolin died on August 15, 1852, in Virmo (Finnish: Mynämäki). The element gadolinium, discovered in 1880, is named after him.

Johan Gadolin is the answer to Guess the Chemist (68).

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Sources

• Rediscovery of the Elements: Yttrium and Johan Gadolin,
  James L. Marshall, Virginia R. Marshall,
  The Hexagon 2008.
• Sir Johan Gadolin of Turku: The grandfather of gadolinium,
  Peter B. Dean, Kirsti I. Dean,
  Acad. Radiol. 1996, 3, S165–S169.
  DOI: 10.1016/S1076-6332(96)80523-X
• The discovery of the elements. XVI. The rare earth elements,
  Mary Elvira Weeks,
  J. Chem. Educ. 1932, 9, 1751.
  DOI: 10.1021/ed009p1751
• Die Entdeckung der Seltenerdmetalle (in German),
  Werner Thum,
  www.chemie-master.de.

Selected Publications by Johan Gadolin

• Inledning til chemien (in Swedish),
  Johan Gadolin, 1798.
• Von einer schwarzen, schweren Steinart aus Ytterby Steinbruch in Roslagen in Schweden (in German),
  Johan Gadolin,
  Crell’s Annalen 1796, 1, 313.