metallocene

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metallocene

chemistry

Also known as: sandwich compound

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June 30, 2026

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Metallocenes are a class of organometallic compounds characterized by a metal atom sandwiched between two planar polyhapto rings. A key example is ferrocene, where an iron atom is situated between two cyclopentadienyl rings. These compounds are known for their stability and can undergo reactions similar to aromatic hydrocarbons.12

Organometallic compounds, in general, contain at least one metal-carbon bond where the carbon atom is part of an organic group. This field is crucial in catalysis, with many industrial processes, particularly in the petroleum and polymer industries, relying on organometallic catalysts. These catalysts are vital for reactions like polymerization, enabling the production of common plastics such as polyethylene and polypropylene.234

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chemistry of industrial polymers
Organometallic catalysis
…new soluble organometallic catalysts, termed metallocene catalysts, have been developed that are much more reactive than conventional Ziegler-Natta catalysts.
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…new soluble organometallic catalysts, termed metallocene catalysts, have been developed that are much more reactive than conventional Ziegler-Natta catalysts.
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chemical bonding
Organometallic compounds
…compounds is composed of the metallocenes, informally called “sandwich compounds,” in which the metal atom sits between two planar hydrocarbon rings, analogous to the meat in a sandwich. Of these, ferrocene [Fe(C₅H₅)₂] was among the first to be synthesized.
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…compounds is composed of the metallocenes, informally called “sandwich compounds,” in which the metal atom sits between two planar hydrocarbon rings, analogous to the meat in a sandwich. Of these, ferrocene [Fe(C₅H₅)₂] was among the first to be synthesized.
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organometallic compound
Cyclic polyene ligands
Their organometallic compounds include the metallocenes ferrocene and bisbenzenechromium and bis(cyclooctatrienyl)uranium (commonly called uranocene), shown here.
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Their organometallic compounds include the metallocenes ferrocene and bisbenzenechromium and bis(cyclooctatrienyl)uranium (commonly called uranocene), shown here.
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Sir Geoffrey Wilkinson
…of other “sandwich” compounds, or metallocenes, and his researches into this previously unknown type of chemical structure earned him the Nobel Prize. His research on metal-to-hydrogen bonding, particularly his discovery of Wilkinson’s catalyst, a homogeneous hydrogenation catalyst for alkenes, had widespread significance for organic and inorganic chemistry and proved to…
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…of other “sandwich” compounds, or metallocenes, and his researches into this previously unknown type of chemical structure earned him the Nobel Prize. His research on metal-to-hydrogen bonding, particularly his discovery of Wilkinson’s catalyst, a homogeneous hydrogenation catalyst for alkenes, had widespread significance for organic and inorganic chemistry and proved to…
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