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{{Short description|Swiss chemist (1838–1911)}}{{Hatnote|For the Canadian comic creator, see Delaf.}}

factoids

Marc Delafontaine (March 31, 1837/1838, Céligny, Switzerland{{efn|name=“b“}}–1911{{efn|name=“d“}}) was a Swiss chemist and spectroscopist who was involved in discovering and investigating some of the rare earth elements.

Career

Delafontaine studied with Jean Charles Galissard de Marignac at the University of Geneva. He also worked at the University of Geneva. Delafontaine moved to the United States of America, arriving in New York in 1870, and later becoming a naturalized citizen. He taught in Chicago, Illinois at city high schools, and at a women’s college.He also worked as an analytical chemist with theChicago Police Department.

Research

Holmium

In 1878, along with Jacques-Louis Soret, Delafontaine first observed holmium spectroscopically.JOURNAL, Thornton, Brett F., Burdette, Shawn C., 20 May 2015, Homely holmium, Nature Chemistry, 7, 6, 532, 2015NatCh...7..532T, 10.1038/nchem.2264, 25991534, free, In 1879, Per Teodor Cleve chemically separated it from thulium and erbium. All three men are given credit for the element’s discovery.BOOK, Fontani, Marco, The Lost Elements: The Periodic Table’s Shadow Side, Costa, Mariagrazia, Orna, Mary Virginia, Oxford University Press, 2014, 9780199383344, 119–125,

Yttrium, terbium and erbium

In 1843, Carl Gustaf Mosander discovered terbium and erbium as components of yttria.BOOK, Tansjö, Levi,books.google.com/books?id=EFzuCAAAQBAJ&q=Mosander, Episodes from the History of the Rare Earth Elements, December 6, 2012, Springer Science & Business Media, 9789400902879, Evans, C. H., 38–55, Carl Gustaf Mosander and His Research on Rare Earths, {{rp|38}}BOOK, Weeks, Mary Elvira,archive.org/details/discoveryoftheel002045mbp, The discovery of the elements, 1956, Journal of Chemical Education, 6th, Easton, PA, {{rp|701}}JOURNAL, Weeks, Mary Elvira, Mary Elvira Weeks, 1932, The discovery of the elements: XVI. The rare earth elements, Journal of Chemical Education, 9, 10, 1751–1773, 1932JChEd...9.1751W, 10.1021/ed009p1751, BOOK, Marshall, James L., Science history : a traveler’s guide, Marshall, Virginia R., October 31, 2014, ACS Symposium Series, 9780841230200, 1179, 209–257, Northern Scandinavia: An Elemental Treasure Trove, 10.1021/bk-2014-1179.ch011, JOURNAL, Piguet, Claude, 21 March 2014, Extricating erbium, Nature Chemistry, 6, 4, 370, 2014NatCh...6..370P, 10.1038/nchem.1908, 24651207, free, However, this discovery was hotly contested. Spectroscopist Nils Johan Berlin denied that the two elements existed, failing to confirm the existence of “erbia” and suggesting that its name be applied to “terbia”. In 1864, Marc Delafontaine used optical spectroscopy to conclusively prove that yttrium, terbium, and erbium were separate elements.BOOK, Friend, John Newton,books.google.com/books?id=CwxDAAAAIAAJ&pg=PA223, A Text-book of Inorganic Chemistry, 1917, Griffin & Company, 9781130017649, 4, 221–223, Ironically, however, the confusion that had been introduced between the names continued. Mosander’s proposed names were switched, giving the amethyst compound the name “erbium” oxide and the yellow substance the name “terbium” oxide, instead of the other way around as originally proposed.JOURNAL, Holden, Norman E., 2001-06-29, History of the Origin of the Chemical Elements and Their Discoverers,www.osti.gov/servlets/purl/789650, Upton, New York, Brookhaven National Laboratory (BNL), BOOK, Krishnamurthy, Nagaiyar,books.google.com/books?id=F0Bte_XhzoAC&pg=PA5, Extractive metallurgy of rare earths, December 16, 2015, CRC Press, 9781466576346, 2nd, 5–7,

References

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Notes

{{notelist|refs={{efn|name=b|Fontani op. cit. p. 125 states that Poggendorff’s Biographisch-Literarisches Handwörterbuch, Verlag von Johan Ambrosius Barth, Leipzig, 1898, p. 344 gives his birthyear as 1838, while Mary Elvira Weeks Discovery of the Elements, 7. ed., Journal of Chemical Education: Easton, Pennsylvania, 1968, p. 677 says it is 1837.}}{{efn|name=d|Fontani op. cit. p. 125 says that no documents exist to report his death but it is assumed Delafontaine passed away in 1911.}}}}{{authority control}}{{Switzerland-scientist-stub}}{{Chemist-stub}}