Fullerenes, by definition only contain hexagonal and pentagonal faces, which form a closed cage structure. Every fullerene has 12 pentagonal faces, and the two smallest fullerenes in which these are all separated and the most stable are C60 and C70. C60 is surprisingly easy to hydrogenate. In benzene, the double bonds are conjugated in such a way that it is more unreactive than it would be if it were a tri-alkene. This however does not apply to C60. It is similar to an alkene, and can easily be hydrogenated to form C60H60 (a fuzzyball).

Because they are hollow, fullerenes are very light for their hardness (1.65gcm-3 compared to 3.51gcm-3 for diamond). They also have the ability to absorb light and can release it at a different frequency, as heat or transfer it to another molecule. This means that they can act as optical limiters. The more light is shone through a solution, the more light they absorb, as the concentration of the excited form of C60 (*C60) increases, and the excess light is emitted as heat. *C60 can also lose it's energy to other molecules. It can convert O2 to highly toxic *O2 with an efficiency of 100%. Therefore in the presence of light and air C60 is highly toxic.

Despite the spherical shape of the molecules, they do not act like ball bearings as you might expect, they fit together like oranges in a box which makes it hard for them to move against each other. This arrangement creates gaps between the C60 molecules. These holes can be filled by small molecules like Group One or Two metals. Some of these metals give this structure superconducting properties at very low temperatures. For example, if rubidium fills all of these holes, below 28K, this material conducts electricity with zero resistance. The rubidium donate an electron to the C60 molecule forming the salt [Rb+]3[C603-] in which electron can move freely.

in C60 every pentagonal face is surrounded by hexagonal faces. If the number of hexagonal faces is increased we can get giant fullerenes beginning with C240 and C540. These can be nested to form structures similar to onions. If one of these giant fillings is stretched a buckytube is formed. These are the narrowest tubes ever made and also the finest fibres. They are incredibly strong and very light. This makes them incredibly useful materials.