Module 1 : Atomic Structure
Lecture 1 : Structural Chemistry
  1.3

The Structure of C60

Carbon is well known to exist in the forms of graphite and diamond. In graphite, the atoms are arranged in a plane, with each atom connecting three other atoms. Adjacent planes are held together by weak interactions (which are much weaker than covalent or ionic interactions). The planes can slide against each other. That is why graphite is used in pencil. In diamond, the atoms are tetrahedrally linked to one another to form a strongly knit three dimensional network. Another allotrope of carbon was discovered in the nineties. This form, buckminsterfullerene (C60) has sixty atoms lying approximately on the surface of a sphere. The structure is shown in Fig 1.3. Other forms such as C70 have also been discovered. These units can be packed to form molecular solids.
 
In Fig 1.3, a C60 which has enclosed a potassium has been shown. This is an example of an ion or a small molecule encased in a larger molecule. The process of encasing is useful for transporting small molecules across membranes or regions wherein direct transport is chemically unfeasible.

 
 

                                                      Figure 1.3: Structure of C60 which has enclosed a potassium ion
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
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