ferrocene

/fer"euh seen'/, n. Chem.

1. Also called dicyclopentadienyliron. an orange, crystalline, water-insoluble coordination compound, (C₅H₅)₂Fe, having a camphorlike odor: used chiefly as an antiknock agent for gasoline and as a catalyst. Cf. metallocene.

2. Also called dicyclopentadienyl metal. any of a class of analogous compounds containing a metal other than iron, as nickel or osmium.

[1950-55; FERRO- + C(YCLOPENTADI)ENE]

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▪ chemical compound

also called  Dicyclopentadienyliron,  

      the earliest and best known of the so-called sandwich compounds; these are derivatives of transition metals in which two organic ring systems are bonded symmetrically to the metal atom. Its molecular formula is (C₅H₅)₂Fe.

      First prepared in 1951 by the reaction of sodium cyclopentadienide with iron(+2) chloride, ferrocene occurs as highly stable orange crystals with a melting point of 174° C (345° F). Chemically, ferrocene behaves like benzene and other aromatic compounds in that it undergoes substitution reactions. The removal of one electron from the molecule raises the iron atom to the next-higher oxidation state (i.e., from +2 to +3), leading to the formation of salts containing the blue ferricinium cation, (C₅H₅)₂Fe⁺.

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