Ferrocene Fe(C5H5)2 is the prototypical metallocene, a
type of organometallic
chemical compound, consisting of two cyclopentadienyl rings bound on opposite sides of a central iron atom and forming an organometallic sandwich compound .
It was first made unintentionally from the reaction of cyclopentadiene and iron powder in the 1950s, originally designed to couple the diene. Instead a lightly orange powder was obtained. The structure was confirmed by NMR. Discovery of its structure led to an explosion of interest in d-block metal carbon bonds and brought about development and the now flourishing study of organometallic chemistry.
In ferrocene, the pi electrons of both the aromatic cyclopentadienyl rings are shared with the central iron ion, giving it an inert gas electron configuration. This makes ferrocene particularly stable.
Ferrocene finds practical application as a catalyst in the making of ultra-high molecular weight polyethylene. This material is a new alternative to aramid, both can be used to make fibres for bulletproof clothing.