June 5, 1760|
|Died||August 15, 1852
Johan Gadolin (5 June 1760 – 15 August 1852) was a Finnish chemist, physicist and mineralogist. Gadolin discovered a "new earth" containing the first rare earth compound yttrium, which was later determined to be a chemical element. He is also considered the founder of Finnish chemistry research, as the second holder of the Chair of Chemistry at the Royal Academy of Turku.
Johan Gadolin was born in Åbo (Finnish name Turku), Finland (then a part of Sweden), as the son of Jakob Gadolin. He began to study mathematics at the Royal Academy of Turku when he was fifteen. Soon he found mathematics too laborious and changed his major to chemistry. In 1779 Gadolin moved to Uppsala University where he was taught by Torbern Bergman.
In 1790, he was elected a member of the Royal Swedish Academy of Sciences.
Gadolin became famous for his description of the first rare earth element, yttrium. In 1792 Gadolin received a sample of black, heavy mineral found in a quarry in the Swedish village Ytterby near Stockholm by Carl Axel Arrhenius. By careful experiments, Gadolin determined that approximately 38% of the sample was a previously unknown "earth", an oxide which was later named yttria. Yttria, or yttrium oxide, was the first known rare earth metal compound — at that time, it was not yet regarded as an element in the modern sense. His work was published in 1794.
In an earlier paper in 1788 Gadolin showed that the same element can show several oxidation states, in his case Sn(II) and Sn(IV) 'by combining itself with larger or smaller amounts of the calcinating substance'. He vividly described the disproportionation reaction:
- 2 Sn(II) Sn(0) + Sn(IV).
One of his latest studies was the chemical analysis of the Chinese alloy pak tong (alpacca, German silver) in 1810 and 1827.
Gadolin became the professor of chemistry at the Royal Academy of Turku in 1797. He was one of the first chemists who gave laboratory exercises to students. He even allowed the students to use his private laboratory. Gadolin wrote the first anti-phlogiston chemistry textbook, Inledning till Chemien (1798) in the Nordic countries.
Gadolin is also famous for publishing one of the earliest examples of counter-current condensers, today usually referred to as Liebig condensers.
- Dean, P B; Dean, K I (August 1996). "Sir Johan Gadolin of Turku: the grandfather of gadolinium.". Academic Radiology 3 (Suppl 2): S165–9. doi:10.1016/S1076-6332(96)80523-X. PMID 8796552.
- Weeks, Mary Elvira (1932). "The discovery of the elements: XVI. The rare earth elements". Journal of Chemical Education 9 (10): 1751–1773. Bibcode:1932JChEd...9.1751W. doi:10.1021/ed009p1751.
- Sella, Andrea (2009). "Gadolin's Condenser". Chemistry World 6 (10): 81–81.
- Pyykkö, Pekka and Orama, Olli (1988). "Johan Gadolin's 1788 paper mentioning the several oxidation states of tin and their disproportionation reaction". Nouveau J. Chimie / New J. Chem. 12: 881–883.
- Pyykkö, Pekka and Orama, Olli (1996). "What did Johan Gadolin actually do?". In Evans, C. H. Episodes from the History of the Rare Earth Elements. Dordrecht: Kluwer. pp. 1–12.
- Moeller, Therald (2013). The Chemistry of the Lanthanides. Pergamon. pp. 39–44. Retrieved 10 March 2015.
- Gadolin, Johan (1794). "Undersökning af en svart tung Stenart ifrån Ytterby Stenbrott i Roslagen". Kongl. Vetenskaps Academiens Nya Handlingar 15: 137–155.
- Enghag, Per (2004). Encyclopedia of the elements technical data, history, processing, applications (1st reprint. ed.). Weinheim: Wiley-VCH. p. 437. ISBN 978-3527306664.