n the world of chemistry, the soccer-ball-shaped molecule called the buckyball is like a child prodigy yet to live up to early acclaim. But after a quiet adolescence, scientists say the buckyball is on the verge of fulfilling some of its early promises.
Named after R. Buckminster Fuller, designer of the geodesic domes they resemble, buckyballs — or, more formally, buckminsterfullerenes — were discovered in 1985. The most common form consists of 60 carbon atoms arrayed in a sphere. In late 1990, after chemists in Arizona and Germany figured out how to make them in more than trace quantities, buckyballs became a scientific craze.
In laboratories around the world, scientists began playing with buckyballs. Some speculated that buckyballs might make good lubricants, slipping and sliding like tiny ball bearings. NASA thought buckyballs might be used as rocket fuel. Medical researchers found they showed promise as an anti- H.I.V. drug. Mixed in with some potassium or rubidium, buckyballs turned into superconductors, transmitting electricity with no loss to resistance. I.B.M., DuPont and Xerox were among the companies to explore possible commercial applications.
Part of the appeal was novelty. Buckyballs are the third fundamental form of carbon, after diamond and graphite. Part of the appeal was that, unlike much in chemistry and physics, buckyballs are easy to describe. In 1991, the journal Science dubbed buckyballs "molecule of the year."
Then they faded out of the news. They reappeared briefly in 1996 when Dr. Richard E. Smalley and Dr. Robert F. Curl Jr. of Rice University in Houston, and Sir Harold W. Kroto of the University of Sussex in England shared the Nobel Prize in Chemistry for the discovery. Then they faded again.
Scientists are still exploring the nature of buckyballs. Last month, researchers at the University of California at Berkeley and the Lawrence Berkeley National Laboratory reported in the journal Nature that they had made a transistor consisting of a single buckyball bouncing between two electrodes. In the same issue, scientists from Boston College and Albert-Ludwigs University in Germany said they had created a carbon ball of only 20 atoms, the smallest of the buckyball family.
But commercial applications have yet to materialize. "Definitely, it's longer than we thought," said Dr. Raouf O. Loutfy, president of Materials and Electrochemical Research Corporation of Tucson, the main manufacturer of buckyballs in the United States.
There are no buckyballs in motor oil or any other lubricants. The rocket fuel idea did not work. AIDS researchers and drug companies embraced protease inhibitors, not the the anti-H.I.V. buckyball compounds.
"In terms of the new science they created, they really have lived up to that hype," said Dr. Robert C. Haddon, who led the research at the former AT & T Bell Laboratories on the superconducting buckyballs. But, he added, "I think perhaps the expectations for applications got overblown. They clearly haven't lived up to that."
Despite a cut in price from $35,000 an ounce in 1990 to $225 an ounce today, Materials and Electrochemical Research still sells only about five pounds a year of the molecules, which look like soot.
Said Dr. Smalley, the Nobel laureate: "Bucky hasn't got a job yet. He's still in school."
In the meantime, many scientists moved on to the next exciting class of carbon molecule: nanotubes, which are stretched-out versions of buckyballs, long cylinders of carbon that resemble rolled-up chicken wire.
"In fact, I myself am not doing much research with buckyballs," Dr. Smalley said. "They're not nearly as interesting as the tubes. Bucky's biggest legacy has been to show us about the tubes."
As they once did about buckyballs, scientists now marvel about the unique properties of nanotubes — they are stronger than steel — and talk of exciting possibilities, including tiny components for quantum computers and the spinning of 22,000-mile-long fibers to build an elevator from the ground to the geosynchronous orbit.
But, as with buckyballs, at least some of the current enthusiasm for nanotubes will hit bumps and dead ends. "There's always two steps in realizing the full potential of a material," said Dr. Haddon, the former Bell Labs researcher. "The first is to get the great properties. The second hurdle — and it's often the most difficult — is to process the materials into a useful form."
Dr. Haddon is confident enough of nanotubes' commercial future to start a company to make them, but he says it is conceivable that nanotubes will stumble against some of the same hurdles that have slowed buckyballs.
Scientists say there are several reasons the original predictions for buckyballs did not unfold as envisioned. Sometimes buckyballs did not behave as hoped — not surprising for a new type of molecule. In other instances, buckyballs did not have any advantage over existing products that would have justified their higher costs.
Xerox, for example, was interested in harnessing the unusual electrical properties of buckyballs to improve the toner in copiers and laser printers. But to do that, buckyballs would have to cost about $1 a pound. "We're way far from that target," said Dr. Ron Ziolo, director of University of Barcelona Xerox Laboratory for Magnetics in Barcelona.
"The buckyballs have been starved for the lack of a way to make them by the ton, more than any other single factor," Dr. Smalley said. "Even if it turned out it had great lubricant properties, that would be irrelevant. That little quart of oil is going to cost a hundred bucks."
Another dead end came in attempts to use buckyballs as a fuel for ion engines. Ion engines, like the one used on the National Aeronautics and Space Administration's Deep Space 1 probe launched in 1998, operate by accelerating charged particles with electric fields. Heavier particles provide more momentum to the engine exhaust, and buckyballs are nearly six times as massive as xenon, the element used as fuel in Deep Space 1.
"So in theory, it would have given you more thrust per unit power," said Dr. Robert Frisbee, a senior staff member of the advanced propulsion technology group at NASA's Jet Propulsion Laboratory.
But buckyballs are also very good at absorbing electrons, and the charged buckyball ions quickly turn back into uncharged buckyballs that do not respond to the electric fields. "That's no way to run an ion engine," Dr. Frisbee said. "It looks good on paper and when you try it in the lab, it doesn't pan out."
The finding that buckyballs can become superconductors was also initially exciting, but never emerged as more than a curiosity. Unlike the high-temperature superconductors discovered a few years earlier, which are stiff and brittle, buckyball materials could be easily shaped. "I thought that the ability to prepare buckyballs as thin films was a real advantage," said Dr. Haddon, now a professor of chemistry at the University of Kentucky.
But buckyballs also react with air and moisture, and they lose their superconducting ability at about minus 400 degrees, warmer than conventional superconductors but considerably lower than the high-temperature superconductors.
As applications for pure buckyballs fell away, chemists developed techniques for adding branches of other molecules to the outside of the buckyballs and for encapsulating atoms within buckyballs. Scientists also explored the properties of larger versions with 70, 76, 78, 80 or 84 carbon atoms.
For researchers still in the field, those efforts look as if they will pay off in medical applications, where the buckyballs' costs are not prohibitively high.
"The buckyball is the raw material for making a whole host of new products," said Dr. Stephen R. Wilson, a professor of chemistry at New York University and a consultant to the Toronto-based company C Sixty Inc., which is looking for medical uses of buckyballs.
In 1993, researchers from the University of California at San Francisco and the University of California at Santa Barbara found that a modified buckyball fits into a cylindrical space in the H.I.V. protease enzyme, which breaks down proteins and disrupts the virus's ability to reproduce.
"H.I.V. looks like a catcher's mitt," Dr. Wilson said. "It has a round hole just about the size of a buckyball."
Other researchers created improved versions that stick better to H.I.V. While generally not as effective as the protease inhibitors now on the market, the anti-H.I.V. buckyballs work even against the resistant strains of H.I.V. and have shown no toxic effects in animal tests, even in high quantities.
C Sixty hopes to begin tests of the compound in people soon. Dr. Uri Sagman, the president of C Sixty, said that if the compound proved safe and effective, it could reach the market in three to five years.
Another buckyball variant may provide treatment for the incurable disease amyotrophic lateral sclerosis, also known as Lou Gehrig's disease. In tests in mice, the molecule, developed by Dr. Laura Dugan, a professor of neurology and medicine at Washington University in St. Louis, delayed the deterioration in movement and extended the animals' lives.
The same electron-absorbing tendency that thwarted the use of buckyballs in ion engines might be the key to slowing down the disease. Free radicals — electrons that damage cells through chemical reactions — have been linked to the destructive powers of the disease.
The buckyballs "are very, very potent antioxidant compounds," Dr. Dugan said.
But she did not know when tests might move from mice to people.
"We can't generate huge amounts," she said. "It is a quantity issue more than anything else." She hopes to enlist the help of a pharmaceutical company.
Dr. Loutfy at Materials and Electrochemical Research said he thought the "killer application" for buckyballs might soon arrive, an application that was not originally foreseen. Scientists at Argonne National Laboratory use buckyballs to make smooth, thin diamond film suitable for coating machine parts. This most promising application of buckyballs involves breaking them apart. Scientists at Argonne's laboratory in Illinois led by Dr. Dieter Gruen, the associate director for the material science division, zap buckyballs with microwaves, causing them to eject pairs of carbons.
The carbon pairs then condense onto a surface of silicon dioxide, forming tiny diamond crystals a few billionths of a meter in size. The crystals pile up to form a thin film.
A similar technique using methane has been used to grow diamond films for 20 years, but the crystals are about one million times as large, and the film surface feels like sandpaper. The buckyball-grown diamond is smooth.
"These films are unique materials with unusual properties that lend themselves to many important applications," Dr. Gruen said. "We're working with about a dozen companies. It is close to commercialization for at least one." He declined to name the companies.
Initial applications of the film may include the rotary shafts in pumps. "They show virtually no wear," Dr. Gruen said.
The process could also lead researchers in the field of micro machines to build their dust-size gears and motors out of diamond instead of silicon. Now, the microscopic motors often wear out in a few minutes, Dr. Gruen said.
Materials and Electrochemical Research, Dr. Loutfy's company, has teamed up with Mitsubishi Corporation and Research Corporation Technologies of Tucson to form Fullerene International Corporation, which has built a larger buckyball factory in Japan.
Dr. Loutfy predicts the diamond films will find a market in a couple of years and could consume 100 tons to 200 tons of buckyballs annually within five years.
With mass production of buckyballs, Dr. Loutfy hopes the price of buckyballs will drop to about $3 an ounce. "Then we could reach a lot of markets," he said.