Laser may loosen the buckeyball's bonds.The intriguing soccer-ball-shaped molecule called a buckyball buckyball, colloquial term for buckminsterfullerene, a roughly spherical fullerene molecule consisting of 60 carbon atoms. Buckytube is a generic term for cylindrical fullerenes. continues to tantalize chemists, who wrestle almost obsessively with the question of how to fill the molecule's empty interior. The problem with this molecule, made of 60 carbon atoms, derives from its stable bonds, which keep the spherical cage dutifully du·ti·ful adj. 1. Careful to fulfill obligations. 2. Expressing or filled with a sense of obligation. du closed. Yet a window does appear to be opening into this otherwise sealed surface. Robert L. Murry and Gustavo E. Scuseria, both chemists at Rice University in Houston, Texas, describe in the Feb. 11 SCIENCE a theoretical mechanism to literally "open a window" into the C60 molecules, as well as related molecules in the fullerene fullerene, any of a class of carbon molecules in which the carbon atoms are arranged into 12 pentagonal faces and 2 or more hexagonal faces to form a hollow sphere, cylinder, or similar figure. family. Tinkering with the tiny carbon cages, the two noticed that certain atomic bonds lend themselves better than others to temporary adjustments. Indeed, the molecule's unique shape comes from an alternating pattern of carbon rings bonded together as hexagons and pentagons -- the pattern found on a soccer ball. Murry and Scuseria realized that the juncture between the pentagons and hexagons, called a "5-6 bond," yields relatively easily to the prying forces of a laser's energy. When properly irradiated, an opening would temporarily appear in the fullerene. This method permits the bond to open widely without disturbing the ball's overall structure, thus permitting one or more atoms -- perhaps even small molecules -- to enter the carbon cage. Furthermore, by opening more than one bond in this way, "multiple windows" are possible. Efforts to "custom-fill the fullerenes' void" continue apace, the researchers say, eyeing potential uses in drug delivery, molecular transport, medical imaging -- even superconducting devices. When "doped," or mixed, with an alkali metal alkali metal Any of the six chemical elements in the leftmost group of the periodic table (lithium, sodium, potassium, rubidium, cesium, and francium). They form alkalies when they combine with other elements. , fullerenes do have the potential to become useful as superconductors. "We'd like to try to make a fullerene superconductor A material that has little resistance to the flow of electricity. Traditional superconductors operate at absolute zero (-459.67 degrees Fahrenheit or -273.15 degrees Celsius). Experiments in the 1980s raised the temperature to -321 degrees Fahrenheit. by putting a lanthanum lanthanum (lăn`thənəm) [Gr.,=to lie hidden], metallic chemical element; symbol La; at. no. 57; at. wt. 138.9055; m.p. about 920°C;; b.p. about 3,460°C;; sp. gr. 6.19 at 25°C;; valence +3. or scandium scandium (skăn`dēəm), metallic chemical element; symbol Sc; at. no. 21; at. wt. 44.9559; m.p. 1,541°C;; b.p. 2,831°C;; sp. gr. 2.99 at 20°C;; valence +3. Scandium is a soft silver-white metal. atom inside the C60 cage," says Scuseria. "This is a very exciting idea, but still theoretical." "Whether it will work," he adds, "remains to be seen." |
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