View source for Eugène-Anatole Demarçay

{{short description|French chemist}}
{{redirect|Demarçay|the historic American hotel|DeMarcay Hotel|the French automobile|De Marçay}}
{{Use dmy dates|date=January 2023}}
{{Infobox scientist
|name              = Eugène-Anatole Demarçay
|image             = File:Demarçay.jpg
|image_size       =151px
|caption           = Eugène-Anatole Demarçay
|birth_date        = 1 January 1852
|birth_place       = [[Paris]]
|death_date        = {{death-date and age|5 March 1903|1 January 1852}}
|death_place       = [[Paris]]
|residence  = 
|citizenship = 
|nationality       = [[France|French]]
|ethnicity         = 
|field             = [[Chemist]]
|work_institutions = 
|alma_mater        = 
|doctoral_advisor  = 
|doctoral_students = 
|notable_students  = 
|known_for         = [[Spectrum]]<br />Discovering the element [[europium]]
|author_abbrev_bot =|author_abbrev_zoo = 
|influences        = 
|influenced        = 
|prizes            = 
|religion = |footnotes = |signature         =
}}

'''Eugène-Anatole Demarçay''' (1 January 1852<ref name="Asimov"/> – 5 March 1903<ref name="Marshall"/>) was a French [[chemist]] who designed an apparatus to produce a spark using an induction coil and used it to generate the spectra of [[Rare-earth element|rare earth elements]] which he examined using [[spectroscopy]], thus detecting the element [[europium]] in 1896, and isolated it as the oxide [[europia]] in 1901. He helped [[Marie Curie]] to confirm the existence of another new [[Chemical element|element]], [[radium]], in 1898.

==Education==
Eugène-Anatole Demarçay was born to  Camille Demarçay (1815–1893) and Cécile Lainé (1829–1916) at 152 boulevard Haussman, [[Paris]].<ref name="Marshall"/> His grandfather Marc-Jean Demarçay (1772–1839) had been a general in the French Revolution. Demarçay studied at the [[Lycée Condorcet]], spent time in England, and in 1870<ref name="Etard" /> entered the [[École Polytechnique]] in [[Palaiseau]] near Paris.<ref name="Weeks" /><ref name="Etard">{{cite journal |last1=Etard |first1=A. |title=The life and work of Eugène Demarçay |journal=The Chemical News and Journal of Physical Science |date=18 March 1904 |volume=89–90 |pages=137–138 |url=https://books.google.com/books?id=KfnmAAAAMAAJ&pg=PA137 |access-date=19 December 2019}}</ref> Demarçay studied under [[Jean-Baptiste Dumas|Jean Baptiste Dumas]] (1800–1884)<ref name="Asimov" /> and served for several years as an assistant to [[Auguste André Thomas Cahours]] at the [[École Polytechnique]].<ref name="Marshall" /> 

In 1876, he studied [[acetylacetonates]] in the laboratory of Cahours.<ref name="Marshall" /> He spent some years travelling to [[Egypt]] and India.<ref name="Weeks" /> In 1880 he completed his dissertation, ''Sur les acides tétrique et oxytétrique et leurs homologues'' ("On tetric and oxytetric acids and their counterparts" Gauthier-Villars, 1880).<ref name="Marshall" /> Some of his early [[organic chemistry]] researches into [[terpenes]] and [[ether]] were important for the [[perfume]] industry.<ref name="Etard" /><ref name="Fontani">{{cite book | last1 = Fontani | first1 = Marco | last2 = Costa | first2 = Mariagrazia | last3 = Orna | first3 = Mary Virginia | year = 2014 | title = The Lost Elements: The Periodic Table's Shadow Side | url =https://books.google.com/books?id=Ck9jBAAAQBAJ&pg=PA211 | publisher = Oxford University Press | pages = 210–212 | isbn = 9780199383344}}</ref><ref>{{Cite journal |last=Wisniak |first=Jaime |date=2021 |title=Eugène Anatole Demarçay |url=https://revista.cnic.edu.cu/index.php/RevQuim/article/view/933 |journal=Revista CENIC Ciencias Químicas |language=en |volume=52 |issue=2 |pages=089–104 |issn=2221-2442}}</ref>

==Career==
Demarçay's interests moved from organic chemistry to [[Organometallic chemistry|organometallics]] and then to [[inorganic chemistry]]. He applied for a professorial position at the [[French Academy of Sciences|Academie des sciences]] in 1878, but was not accepted.<ref name="Marshall"/>

He became particularly interested in studying [[nitrogen sulfides]], publishing three papers in 1880–1881. These compounds appear stable at room temperature, but are sensitive to heat, friction, and shock, and are likely to explode when heated.<ref name="Marshall"/> During an experiment with [[nitrogen]] and [[sulfur]], a cast-iron vessel exploded and destroyed the sight in one of his eyes.<ref name="Etard"/><ref name="Asimov"/>

He established his own private laboratory at 2 Boulevard Berthier, Paris.<ref name="Marshall"/> In 1881–1882, he developed a vacuum system to control temperature during experiments.<ref name="Marshall"/> 1.5 metres high, it consisted of 3 concentric vessels and a compressor driven by a six horsepower gas engine. Temperature in the center vessel could be reduced to −85&nbsp;°C.<ref name="Etard"/> Demarçay used this to study the volatility of substances such as [[zinc]], [[cadmium]], and [[gold]] at low temperatures.<ref name="Marshall"/>

Demarçay became a specialist in reading the line patterns of [[spectroscopy]]. He developed new techniques for the identification of spectra from rare earth metals.<ref name="Enghag"/> He developed an instrument for obtaining spectra,<ref name="Marshall"/> using an [[induction coil]] with pure [[platinum]] electrodes to produce a high spark temperature that eliminated impurities that could cause foreign spectral lines. By eliminating sources of error, he made it possible to separate out purer samples of various rare earths than had previously been available.<ref name="Etard"/><ref name="Enghag">{{cite book|last1=Enghag|first1=Per|title=Encyclopedia of the elements: technical data, history, processing, applications|date=2004|publisher=Wiley-VCH|location=Weinheim|isbn=978-3527306664|pages=452–|edition=1st reprint|url=https://books.google.com/books?id=fUmTX8yKU4gC&pg=PA452}}</ref>

In 1896, he suspected that samples of the recently discovered element [[samarium]] were contaminated with another unknown element, predicting that it would be located between samarium and [[gadolinium]].  To obtain pure enough samples, he developed a new separation technique involving crystallization of double magnesium nitrate salts. By 1901, he had isolated samples of sufficient purity to confirm the isolation of [[europium]].<ref name="Etard"/><ref name="Weeks"/><ref name="XVI">{{cite journal | author-last = Weeks|author-first= Mary Elvira |authorlink=Mary Elvira Weeks| title = The discovery of the elements. XVI. The rare earth elements | journal = Journal of Chemical Education | year = 1932 | volume = 9 | issue = 10 | pages = 1751–1773  | doi = 10.1021/ed009p1751 |bibcode= 1932JChEd...9.1751W }}</ref><ref>{{cite journal|url = http://gallica.bnf.fr/ark:/12148/bpt6k30888/f1580.image| journal = [[Comptes rendus de l'Académie des sciences|Comptes rendus]]| first = Eugène-Anatole|last = Demarçay|title = Sur un nouvel élément l'europium|volume = 132|pages = 1484–1486|date = 1901}}</ref>

In 1898, using his skills of spectroscopy, he help [[Marie Curie|Marie]] and [[Pierre Curie]]  confirm  the isolation of a new element, [[radium]]. After extracting [[polonium]] from [[pitchblende]] they observed that the remaining sample was still radioactive. They consulted Demarçay, who reported a  line in the spectrograph indicative of a new element.<ref name="Malley">{{cite book |last1=Malley |first1=Marjorie C. |title=Radioactivity : a history of a mysterious science |date=2011 |publisher=Oxford University Press |isbn=9780199766413 |url=https://books.google.com/books?id=gI-OWe_2QbkC&pg=PT39 |access-date=18 December 2019}}</ref><ref name="Asimov">{{cite book |last1=Asimov |first1=Isaac |title=[[Asimov's Biographical Encyclopedia of Science and Technology]]|chapter=825. Demarçay, Eugène Anatole |date=1982 |publisher=Doubleday |location=New York etc. |pages=532–533 |edition=2nd revised |url=}}</ref><ref name="Weeks">{{cite book |last1=Weeks |first1=Mary Elvira |title=The discovery of the elements |date=1956 |publisher=Journal of Chemical Education |location=Easton, PA |url=https://archive.org/details/discoveryoftheel002045mbp |edition=6th }}</ref>{{rp|718–720}}<ref name="Daintith">{{cite book |last1=Daintith |first1=John |title=Biographical Dictionary of Scientists|chapter=Demarcay, Eugene Anatole |date=1994 |publisher=Institute of Physics Publishing|location=Bristol and Philadelphia |edition=2nd|volume=1st|page=219}}</ref>

==Awards==
* 1881, Jecker Prix, Section de Chimie de L' Academie des Sciences for contributions to organic chemistry<ref name="Marshall"/>

==Family==
On 14 November 1889 Demarçay married Jeanne Berard (1865–1933) at the Temple du St. Esprit, Paris, in a  Protestant wedding. His granddaughter, Joseph de Carayon Talpayrac, was alive in Paris in 2003.<ref name="Marshall"/>

Eugène-Anatole Demarçay died 5 March 1903, at his home at 80 Boulevard Malesherbes, Paris. His brother Jean became executor of his estate, and offered the state of the art equipment from his laboratory to Pierre Curie. Curie eventually arranged for it to be given to rare earths researcher [[Georges Urbain]].<ref name="Marshall">{{cite journal |last1=Marshall |first1=James L. |last2=Marshall |first2=Virginia R. |title=Rediscovery of the Elements: Europium-Eugene Demarçay |journal=The Hexagon |date=2003 |issue=Summer |pages=19–21 |url=http://www.chem.unt.edu/~jimm/REDISCOVERY%207-09-2018/Hexagon%20Articles/demarcay%20and%20europium.pdf |access-date=18 December 2019}}</ref><ref name="Virginia">{{cite journal |last1=Marshall |first1=James L. Marshall |last2=Marshall |first2=Virginia R. Marshall |title=Rediscovery of the elements: The Rare Earths–The Confusing Years |journal=The Hexagon |date=2015 |pages=72–77 |url=http://www.chem.unt.edu/~jimm/REDISCOVERY%207-09-2018/Hexagon%20Articles/rare%20earths%20II.pdf |access-date=30 December 2019}}</ref>

==Publications==
*''Spectres électriques. Atlas'' ; Eugène Demarçay ; Paris : Gauthier-Villars, 1895. {{OCLC|54317437}}
*''Sur les acides tétrique et oxytétrique et leurs homologues'' ; Eugène Demarçay ; Paris : Gauthier-Villars, 1880. {{OCLC|25644291}}

==References==
{{reflist}}

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{{DEFAULTSORT:Demarcay, Eugene-Anatole}}
[[Category:19th-century French chemists]]
[[Category:1852 births]]
[[Category:1903 deaths]]
[[Category:Discoverers of chemical elements]]
[[Category:Europium]]
[[Category:Samarium]]
[[Category:20th-century French chemists]]
[[Category:Rare earth scientists]]