What are fullerenes? How are they prepared ?

Explanation

Fullerenes are the crystalline form of carbon. They consist of cluster of carbon atoms such as `C_(32),C_(50),C_(70),C_(84)`. etc. They are cage like molecules. `CO_(60)` has soccer ball like shape.
Preparation : Firstly, these were prepared by evaporation of graphite using a powerful laser. But later on, they are prepared by heating graphite in an electric arc in the presence of inert gas like helium or argon. A sooty material is formed by the condensation of `C_(n)` small molecules. It consists of `C_(60)` fullerenes with little amount of `C_(70)` and some traces of other fullerenes having even number of carbon atoms up to 350 or above. `C_(60)` and `C_(70)` can be easily separated out from its soot by extraction with benzene or toluene. It is done by chromatography over alumina. Fullerenes dissolve in the organic solvents and give coloured solutions.