What makes buckyballs so important

This cover story, written by Edward Edelson and originally published in the August issue of Popular Science, explores how buckyballs were accidentally discovered and the future of possibilities to those scientists in A revolution in chemistry is taking place in a small room in a converted mining building in Tucson, Ariz.

The reason? Together with the plain-Jane carbon particles that make up most of the soot is a carbon molecule with a unique structure, totally different from that of the two previously known forms of carbon. The discovery of a new kind of carbon came as a stunning surprise to most scientists. Carbon is the most intensely studied of all the elements because it is the basis for most ofthe molecules of life—the organic molecules. Look in any chemistry textbook and youll read that for centuries research showed carbon came in just two basic structures: hard, sparkling diamond, whose carbon atoms are arranged in little pyramids; and dull, soft, slippery graphite, which consists of sheets of carbon-atom hexagons.

Those chemistry textbooks are now obsolete. It is the only molecule of a single element to form a spherical cage. Informally, chemists call it buckyball, or C Its atoms are arrayed in a collection of regular pentagons and hexagons—12 pentagons and 20 hexagons to be precise.

Scientists have called this whole family the fullerenes; scores of chemists and physicists are working full blast to unravel their properties. To explain, he harkens back to the discovery of benzene in Now chemists hope to perform the same magic with this family of new carbon molecules that is at least 10 times bigger than benzene, with, therefore, even greater possibilities.

It is now clear to researchers that the C molecule is exceptionally stable and resistant to radioactivity and chemical corrosion. It also greedily accepts electrons, but is not reluctant to release them. These and other attributes have scientists and engineers already speculating about microscopic ball bearings, new cancer treatments, lightweight batteries, powerful rocket fuels, and the infinite possibilities in plastics and other organic compounds that have carbon atoms as their backbones.

One proposal for anti-tumor therapy in cancer patients is to enclose radioactive atoms inside buckyballs. The carbon barrier would help maintain the integrity of the radioisotopes after injection. Another idea Smalley talks about is creating a superpowerful battery by wrapping lithium and fluorine atoms, which create energy when they combine, inside a buckyball cage to protect them from being attacked by oxygen in the air.

Other researchers imagine batteries that can be made by stripping away some electrons from the new molecule. Scientists speculate about stringing buckyballs together to form the basis of new types of plastics.

They dream of altering the molecule in a million ways by hanging different atoms or chemical groups from the 60 carbons. The story behind the discovery of the buckyball is as bizarre as its structure. Go back to to Rice University, where a team headed by Smalley was investigating the properties of atomic clusters, groups of atoms larger than molecules but smaller than visible solids. The Smalley team was using an unusual device they had invented, called the laser-supersonic cluster beam apparatus.

A sample placed inside the block is zapped by a very intense, short pulse of laser energy that vaporizes it. At the moment of zapping, a whiff of inert helium gas carries the vaporized material toward another laser, which ionizes the clusters by stripping away electrons.

The clusters are then pushed into an analytical instrument called a mass spectrometer, which gives a reading of their size. Smalley was using the machine on a variety of elements, including silicon. Kroto was interested in this because he was working on the possible origins of long-chain carbon molecules in interstellar space; he had found evidence of a nine-carbon molecule in the dust between stars. He theorized that carbon molecules might be forged in the atmospheric furnaces of red giant stars that are rich in carbon.

When a star has burned about 10 percent of its hydrogen fuel, it swells to a much greater size and becomes redder and much brighter. When our sun becomes a red star in a few billion years, it will gobble up Mercury and Venus. They had expected a similarly random, and uninteresting, assortment of carbon clusters like that found by the Exxon people.

Most of those contained from 2 to 30 carbon atoms, with some much larger clusters of even-numbered atoms. Wohler, however, had shown that organic molecules were not characterized by any mysterious force, their common feature was that they all contained carbon atoms.

And these carbon atoms readily joined to each other as well as to other atoms in a myriad ways giving rise to a vast array of organic compounds ranging from fats and proteins to the flavour of vanilla and the odour of a rose.

Diamond, graphite and buckyballs are examples of the variety of ways carbon atoms can join together, and are particularly interesting because they contain only carbon atoms. In diamond the atoms are arranged in a three dimensional lattice, while in graphite they are joined together in an array of planar six membered rings, arranged in layers.

The diamond is very hard while the possible movement of the layers in graphite makes it into an excellent lubricant. The curious name comes from the geodesic dome concept pioneered by architect Buckminster Fuller.

Two years later, scientists discovered particles of buckyballs in the gas orbiting around a star — essentially stacked up buckyballs in a single mass — adding weight to the initial NASA observations. And in , the Hubble Space Telescope provided the most concrete evidence of buckyballs in space yet. It detected the spherical molecules floating around in interstellar medium.

These observations defied a prevailing theory of the limits of the universe: that only light molecules, composed of one to ten atoms, could ever be present. Instead, these buckyballs contained up to Carbon atoms. But then again, nothing about buckyballs is conventional. Interstellar space is mostly made up of hydrogen and helium, and carbon atoms are known to bond with different kinds of atoms.

So finding a cluster of pure carbon atoms at all puzzled scientists. The consensus among scientists had been that intense radiation — such as that emitted by a dying star — would kill off any complex molecules, including buckyballs, in space.

Buckyballs are composed of carbon atoms linked to three other carbon atoms by covalent bonds. However, the carbon atoms are connected in the same pattern of hexagons and pentagons you find on a soccer ball, giving a buckyball the spherical structure as shown in the following figure.

The most common buckyball contains 60 carbon atoms and is sometimes called C Other sizes of buckyballs range from those containing 20 carbon atoms to those containing more than carbon atoms.