1.1 Buckyballs: their history and discovery  (Page 4/6)

Eleven days after they had begun, the scientist submitted their discovery to the prestigious journalNature in a manuscript titled “C60 Buckminsterfullerene.” The journal received it on the 13th of September and published it onthe 14th of November 1985. The controversial discovery sparked approval and criticism for a molecule that was remarkablysymmetrical and stable.

How buckyballs are made?

Experimentally, Smalley, Kroto, and Curl, first created the buckyballs using Smalley’s laser-supersoniccluster beam apparatus to knock carbons off of a plate and into a high pressure stream of helium atoms. They would be carried off andimmediately be cooled to only a few degrees above absolute zero, where they would aggregate and form these buckyballs. This methodhowever, resulted in low yields of buckyballs, and it took nearly five years until in 1990 newer methods developed by American andGerman scientists could manufacture buckyballs in large quantities.

The common method today involves transmitting a large current between two graphite electrodes in an inertatmosphere, such as Helium. This gives rise to a carbon plasma arc bridging the two electors, which cools instantaneously and leavesbehind a sooty residue from which the buckyballs can be extracted.

These methods of producing buckyballs do deserve a great deal of applaud. However, humans cannot take all,or even most of, the credit for the production of fullerenes. As a matter of fact, buckyballs occur in nature, naturally, and ingreater amounts than expected. Buckyballs are known to exist in interstellar dust and in geological formations on Earth. Evencloser to home are the buckyballs that naturally form in the wax and soot from a burning candle, as the flame on the wick providesthe sufficient conditions for such processes to occur. Buckyballs are the new sensation for us, but to Nature, they are oldnews.

Chemical and physical properties

Since buckyballs are still relatively new, there properties are still being heavily studied. Buckyballs’unique shape and electron bonding give them interesting properties on the physical level, and on the chemical level.

Since spheres in nature are known to be the most stable configurations, one could expect the same fromfullerenes. Indeed this is one of the reasons why Smalley, Curl, and Kroto initially considered its shape. Their tests showed thatit was extremely stable, and thus, they reasoned, it could be a spherical-like geodesic. Also, fullerenes are resilient to impactand deformation. This means, that squeezing a buckyball and then releasing it would result in its popping back in shape. Or perhaps,if it was thrown against an object it would bounce back; ironically just like the very soccer ball it resembles.

Buckyballs are also extremely stable in the chemical sense. Since all the carbon-carbon bonds are optimized intheir configuration, they become very inert, and are not as prone to reactions as other carbon molecules. What makes these bondsspecial is a property called aromaticity. Normally, electrons are fixed in whatever bond they constitute. Whereas in aromaticmolecules, of which hexagonal carbon rings are a prime example, electrons are free to move (“delocalize”) among other bonds. Sinceall the fullerenes have the cyclo-hexanes in abundance, they are very aromatic, and thus have very stable, inert, carbon bonds.Buckyballs, though sparingly soluble in many solvents, are in fact the only known carbon allotropes to be soluble.