Editing Ferrocene (section)

===Early methods===
The first reported syntheses of ferrocene were nearly simultaneous. Pauson and Kealy synthesised ferrocene using iron(III) chloride and cyclopentadienyl magnesium bromide.<ref name=pauson/> A [[redox|redox reaction]] produces iron(II) chloride. The formation of fulvalene (the intended outcome), does not occur.<ref name = Pauson2001>{{cite journal|title = Ferrocene&mdash;how it all began| vauthors = Pauson PL |author-link = Peter Pauson|journal = [[Journal of Organometallic Chemistry]]|volume = 637–639|year = 2001|pages = 3–6|doi = 10.1016/S0022-328X(01)01126-3}}</ref>
:[[File:Kealy and Pauson synthesis of ferrocene v2.jpg|600px]]

[[File:Miller Ferrocen Synthese.svg|thumb|300px|The Miller ''et al.''<ref name=miller/> approach to ferrocene|left]]
Another early synthesis of ferrocene was by Miller ''et al.'',<ref name=miller/> who treated metallic iron with [[gas]]eous cyclopentadiene at elevated temperature.<ref>{{cite journal | vauthors = Wilkinson G, Pauson PL, Cotton FA |author-link1=Geoffrey Wilkinson |author-link3=F. Albert Cotton |doi=10.1021/ja01636a080|title=Bis-cyclopentadienyl Compounds of Nickel and Cobalt|year=1954|journal=[[J. Am. Chem. Soc.]]|volume=76|pages=1970–1974|issue=7}}</ref> An approach using [[iron pentacarbonyl]] was also reported.<ref>{{cite book | vauthors = Wilkinson G, Cotton FA |author-link1=Geoffrey Wilkinson |author-link2=F. Albert Cotton |doi=10.1002/9780470166024.ch1|year=1959 |chapter=Cyclopentadienyl and Arene Metal Compounds|title=Progress in Inorganic Chemistry|volume=1|pages=1–124|isbn=978-0-470-16602-4}}</ref>

:Fe(CO)<sub>5</sub> + 2&nbsp;C<sub>5</sub>H<sub>6</sub> → Fe(C<sub>5</sub>H<sub>5</sub>)<sub>2</sub> + 5&nbsp;CO + H<sub>2</sub>