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What are endohedral fullerenes?
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fullerene
Two fullerene structures: an elongated carbon nanotube and a spherical buckminsterfullerene, or “buckyball.”
Endohedral fullerenes are a specialized class of fullerene compounds in which an atom or small molecule is physically trapped inside the hollow carbon cage. These complexes are typically denoted by the formula M@C, where M represents the encapsulated atom and C represents the fullerene cage.1
Key characteristics of these compounds include:
- Composition: Various substances can be encapsulated, including alkali metals, alkaline earth metals, early lanthanoids, and even helium.1
- Synthesis: They are often produced by vaporizing graphite disks or rods that have been impregnated with the desired metal. Alternatively, helium can be trapped by heating C in helium vapor under pressure.1
- Scientific Significance: The size of the encapsulated atom determines the minimum size required for the surrounding cage. Research into these species, such as finding helium-filled fullerenes in meteorites, provides valuable insights into the origins of the bodies where they are discovered.1