Editing Paul-Émile Lecoq de Boisbaudran (section)

=== Gallium ===
[[File:Gallium Pellets.jpg| thumb|right| Gallium]]
A significant achievement of Lecoq de Boisbaudran was his discovery of the element [[gallium]] in 1875. Beginning in 1874, Lecoq de Boisbaudran investigated a sample of 52&nbsp;kg of the mineral ore [[sphalerite]] obtained from the Pierrefitte mine in the [[Pyrenees]]. From it, he extracted several milligrams of gallium chloride. Using spectroscopic methods, he observed what appeared to be two previously unreported lines in the sample's spectrum, at wavelengths of 4170 and 4031 [[angstroms]].<ref name="Ramsay"/><ref name="Weeks"/>

[[File:Spectre electrique du Chlorure de Gallium.jpeg|thumb|right|Spectre electrique du Chlorure de Gallium, 1877]]
He continued his experiments using several hundred kilograms of crude zinc ore and in the same year isolated more than one gram of a near-pure metal by electrolysis of a solution of the metal in its form as a hydroxide compound, dissolved in [[potassium hydroxide]] solution. Later he prepared 75&nbsp;grams of gallium using more than 4 tonnes of crude ore. He confirmed its spectral characteristics, consisting of two spectral lines in the [[violet (color)|violet]] portion of the spectrum of the mineral sphalerite. In this way, he ruled out the possibility that the spectral characteristics were an accident of the extraction process, rather than being an indication of a new element.<ref name="Bois">{{cite journal |title= Caractères chimiques et spectroscopiques d'un nouveau métal, le gallium, découvert dans une blende de la mine de Pierrefitte, vallée d'Argelès (Pyrénées) |first=Paul Émile  |last= Lecoq de Boisbaudran |pages=493–495 |journal= Comptes Rendus Hebdomadaires des Séances de l'Académie des Sciences |volume= 81 |date= 1875 }}</ref><ref name="Weeks"/>

He named his discovery "gallium", from the [[Latin]] ''Gallia'' meaning [[Gaul]], in honor of his native land of France. It was later suggested that Lecoq de Boisbaudran had named the element after himself, since ''gallus'' is the Latin translation of the French ''le coq''. Lecoq de Boisbaudran denied this suggestion in an article in 1877.<ref name="XIII">{{cite journal |title= The discovery of the elements. XIII. Some elements predicted by Mendeleeff |pages= 1605–1619 |last= Weeks |first= Mary Elvira |author-link=Mary Elvira Weeks |doi=10.1021/ed009p1605 |journal= [[Journal of Chemical Education]] |volume= 9 |issue= 9 |date= 1932 |bibcode= 1932JChEd...9.1605W}}</ref> He published an account of his investigations on the new element in ''Sur un nouveau metal, le gallium'' (1877).<ref>{{cite book |last1=Lecoq de Boisbaudran |first1=[Paul-Émile] |title=Sur un nouveau metal, le gallium |date=1877 |publisher=s.n. |location=Paris}}</ref>

De Boisbaudran calculated the atomic mass of gallium as 69.86, close to the currently accepted value of 69.723.<ref name="Ramsay"/><ref name="Gordin"/> Unknown to Lecoq de Boisbaudran,<ref name="Weeks"/> the existence of gallium had been predicted during 1871 by [[Dmitri Mendeleev]], who gave it the name ''eka-aluminium''. De Boisbaudran's discovery of gallium was significant support for Mendeleev's theory of the [[periodicity of the elements]].<ref name="Gordin"/><ref name="Ramsay"/><ref name="Ebbing">{{cite book |last1=Ebbing |first1=Darrell |last2=Gammon |first2=Steven D. |title=General chemistry |date=2010 |publisher=Brooks/Cole Cengage Learning |isbn=9780538497527 |page=312 |edition=Enhanced., 9th |quote= "In 1874 the French chemist Paul-Émile Lecoq de Boisbaudran found two previously unidentified lines in the atomic spectrum of a sample of sphalerite (a zinc sulfide, ZnS, mineral). Realizing he was on the verge of a discovery, Lecoq de Boisbaudran quickly prepared a large batch of the zinc mineral, from which he isolated a gram of a new element. He called this new element gallium."}}</ref>