Delafontaine moved to the United States of America, arriving in New York in 1870,[2] and later becoming a naturalized citizen.[1]
He taught in Chicago, Illinois at city high schools,[2] and at a women's college.[1]
He also worked as an analytical chemist with the
Chicago Police Department.[2]
In 1843, Carl Gustaf Mosander discovered terbium and erbium as components of yttria.[4]: 38 [2]: 701 [5][6][7]
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".[8]
In 1864, Marc Delafontaine used optical spectroscopy to conclusively prove that yttrium, terbium, and erbium were separate elements.[8] 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.[9][10][7][8]
References
^ abcdFontani, Marco; Costa, Mariagrazia; Orna, Mary Virginia (2014). The Lost Elements: The Periodic Table's Shadow Side. Oxford University Press. pp. 119–125. ISBN9780199383344.
^Marshall, James L.; Marshall, Virginia R. (October 31, 2014). "Northern Scandinavia: An Elemental Treasure Trove". Science history : a traveler's guide. Vol. 1179. ACS Symposium Series. pp. 209–257. doi:10.1021/bk-2014-1179.ch011. ISBN9780841230200.
^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.
^Fontani op. cit. p. 125 says that no documents exist to report his death but it is assumed Delafontaine passed away in 1911.