Structural formula
name Ferrocen
other names Dicyclopentadienyleisen, Bicyclopentadienyleisen
sum formula C 10 H 10 Fe
CAS number 102-54-5
short description orange crystals
mol mass 186.04 g mol
state of aggregation firmly
density g/cm ³
melting point 172-175 °C
boiling point 249 °C
steam pressure 3.4 h Pa (100 °C)
solubility solubly in organic(nonpolar) solvents, insolubly in water
of safety references
of Gefahrensymbole
injurious to health
environmentally hazardous
R and S-sentences

of R: 22-51/53
S: 61

As far as possible and common, SI-UNITs are used. If not differently notes, the indicated data apply with standard conditions.

Ferrocen (Dicyclopentadienyleisen or Bicyclopentadienyleisen) is metal Organizations for economic cooperation and development, i.e. an metal-organic connection with aromatic ring systems, and was first of these connections, which were called Sandwichverbindung, because it showed up that the two Cyclopentadienylringe were on opposite sides of the iron atom. The sum formula is C 10 H 10 Fe.

Table of contents


Ferrocen forms orange Kristallnadeln with a melting point of 171 °C and for a boiling point of 249 °C. In water Ferrocen is insolubly, soluble in nonpolar solvents such as hexane or toluol however well. Itlarge thermal and chemical stability possesses.

connection conditions

Ferrocen formally consists of an iron (II) - cation and two Cyclopentadienyl anions (C 5 H 5 -). Altogether thus an uncharged complex results. Connection conditions can one explain oneself simplified as follows: The Cyclopentadienyl anions orderas aromatics over a delokalisiertes π-Elektronensystem. Each of these two ligands can put 6 π-electrons to the Fe (II) - cation at the disposal. Since the iron (II) - cation over 24 electrons possesses, and altogether to still 12 electrons of the ligands, possesses it receives 24 + 12 = 36 electrons in the complex.Thus it, the 18-Elektronen-Regel achieves following, the energetically favorable noble gas configuration of krypton.

historical information

1951 were kept coincidental from Kealy and Pauson with the reaction from iron powder with Cyclopentadien as orange crystals, which were surprisingly air stable and easily are sublimatedcould. Independently the working group likewise manufactured Ferrocen around Miller and described.

The first structure suggestions by infrared spectrophotometry of Wilkinson and Woodward (at that time both to the Harvard University) could be confirmed to 1952 by X-raying crystal analysis by Fischer and Pfab (both DO Munich at that time).

Ernst OttoFischer and Geoffrey Wilkinson received the Nobelpreis for chemistry for their work to 1973 over metal-organic connections, which explained also connection conditions in the Ferrocen.


Ferrocen is added to the fuel oil (ESSO formula plus), whereby a higher burn temperature and a better Ausbrand reachbecomes.

In the Zyklovoltammetrie Ferrocen is often used because of its reversible oxidation for the Ferrocenium ion as reference substance in not aqueous solutions.


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