View source for Nitrogen fixation

=== Historical ===
A method for nitrogen fixation was first described by [[Henry Cavendish]] in 1784 using electric arcs reacting nitrogen and oxygen in air. This method was implemented in the [[Birkeland–Eyde process]] of 1903.<ref>{{cite journal| title= The Manufacture of Nitrates from the Atmosphere by the Electric Arc—Birkeland-Eyde Process | vauthors = Eyde S | journal= Journal of the Royal Society of Arts| volume= 57| issue = 2949 | year= 1909| pages= 568–576 | jstor=41338647}}</ref> The fixation of nitrogen by lightning is a very similar natural occurring process.

The possibility that atmospheric nitrogen reacts with certain chemicals was first observed by M. Desfosses, a pharmacist from [[Besançon]],<ref>{{Cite journal|url=https://books.google.com/books?id=-fxBAAAAcAAJ|title=désoxidation de la teinture de tournesole.|last=Desfosses|first=M.|date=1828|journal=Journal de pharmacie et des sciences accessoires|issue=XI|volume=14|pages=478,487|language=French}}</ref> in 1828.<ref>{{Cite journal|url=https://books.google.com/books?id=-fxBAAAAcAAJ|title=Sur la formation de cyanure de potassium|last=Desfosses|first=M.|date=1828|journal=Journal de pharmacie et des sciences accessoires|issue=5|volume=14|pages=280–284|language=French}}</ref> He observed that mixtures of [[alkali metal]] oxides and carbon react with nitrogen at high temperatures. With the use of [[barium carbonate]] as starting material, the first commercial process became available in the 1860s, developed by Margueritte and Sourdeval. The resulting [[barium cyanide]] reacts with steam, yielding ammonia. In 1898 [[Adolph Frank|Frank]] and [[Nikodem Caro|Caro]] developed what is known as the [[Frank–Caro process]] to fix nitrogen in the form of [[calcium cyanamide]]. The process was eclipsed by the [[Haber process]], which was discovered in 1909.<ref>{{cite journal |title=Die Umwandlungsgleichung Ba(CN)<sub>2</sub> → BaCN<sub>2</sub> + C im Temperaturgebiet von 500 bis 1000&nbsp;°C |trans-title=The conversion reaction Ba(CN)<sub>2</sub> → BaCN<sub>2</sub> + C in the temperature range from 500 to 1,000&nbsp;°C | vauthors = Heinrich H, Nevbner R | journal = Z. Elektrochem. Angew. Phys. Chem. | volume = 40 | issue = 10 | pages = 693–698 | year = 1934 | url = http://onlinelibrary.wiley.com/doi/10.1002/bbpc.19340401005/abstract |url-access=subscription | access-date = 8 August 2016 | doi = 10.1002/bbpc.19340401005 |s2cid=179115181 | archive-url = https://web.archive.org/web/20160820203326/http://onlinelibrary.wiley.com/doi/10.1002/bbpc.19340401005/abstract | archive-date = 20 August 2016 | url-status = live }}</ref><ref>{{cite book |url={{google books |plainurl=y |id=87XQAAAAMAAJ}}|title=Fixed nitrogen|year=1932|last=Curtis|first=Harry Alfred|publisher=Chemical Catalog Company}}</ref>