Marc Delafontaine

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Marc Delafontaine (March 31, 1837/1838, Céligny, SwitzerlandTemplate:Efn–1911Template:Efn) 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.<ref name="Fontani" />

Delafontaine moved to the United States of America, arriving in New York in 1870,<ref name="Weeks" /> and later becoming a naturalized citizen.<ref name="Fontani" /> He taught in Chicago, Illinois at city high schools,<ref name="Weeks" /> and at a women's college.<ref name="Fontani" /> He also worked as an analytical chemist with the Chicago Police Department.<ref name="Weeks" />

Research

Holmium

In 1878, along with Jacques-Louis Soret, Delafontaine first observed holmium spectroscopically.<ref name="Thornton">Template:Cite journal</ref> In 1879, Per Teodor Cleve chemically separated it from thulium and erbium. All three men are given credit for the element's discovery.<ref name="Fontani">Template:Cite book</ref>

Yttrium, terbium and erbium

In 1843, Carl Gustaf Mosander discovered terbium and erbium as components of yttria.<ref name="Tansjö">Template:Cite book</ref>Template:Rp<ref name="Weeks">Template:Cite book</ref>Template:Rp<ref>Template:Cite journal</ref><ref name="Marshall">Template:Cite book</ref> <ref name="Piguet">Template:Cite journal</ref> 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".<ref name="Friend" />

In 1864, Marc Delafontaine used optical spectroscopy to conclusively prove that yttrium, terbium, and erbium were separate elements.<ref name="Friend">Template:Cite book</ref> 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.<ref name="Holden">Template:Cite journal</ref><ref name="Krishnamurthy">Template:Cite book</ref><ref name="Piguet" /><ref name="Friend" />

Notes

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