BABY buckyballs should have unusual electrical properties, but nobody has been able to make enough of them to find out. Now Chinese scientists have worked out how to make C50 buckyballs in large quantities for the first time.
Standard buckyballs, properly called buckminsterfullerenes, are hollow spherical molecules in which 60 carbon atoms form a net of pentagons and hexagons that resemble the panels on a soccer ball. Since they were first created artificially in 1985, they have become the focus of global research efforts to exploit their unusual electrical, chemical and mechanical properties.
C50 is more difficult to create because it violates the 鈥渋solated pentagon rule鈥�, which states that a three-dimensional buckyball structure will fall apart if the edges of two of its pentagon faces touch. The trick perfected by Su-Yuan Xie and colleagues at Xiamen University in south-east China was to use a ring of 10 chlorine atoms as a molecular scaffold to support the structure, holding it together like a belt.
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The usual way to make ordinary buckyballs on a large scale is to vaporise carbon in an electric arc, and then allow it to reform in soccer-ball shapes. The Chinese team simply added chlorine to this mix to make C50. They say it may be possible to make large quantities of even smaller buckyballs in the same way (Science, vol 304, p 699).
Laszlo Mihaly, a buckyball researcher at Stony Brook University in New York, says the molecules may turn out to have unusual conducting characteristics because the carbon atoms should conduct electricity well, while the chlorine atoms should act as insulators. But the only way to tell is to make the stuff in large quantities and test it. 鈥淲e do not have the capacity to predict the properties of such solids,鈥� he says.