Something I've been working on myself when I free time from my Thread Topic Generator.
In the fullerenes, the bonds are like those of benzene and graphite, with a shimmer of electrons moving over the surface of the balls.
(But C60 can be hydrogenated, right up to C60H60, buckminsterfullerane, or fluorinated to C60Fl60, super-teflon, the hydrogen or fluorine atoms sticking out to make "fuzzyballs".)
When the balls are stacked together they pack neatly, just as individual atoms do in crystals. Pure C60 is an electrical insulator, but if it is doped with three potassium ions , forming a "fulleride", the shimmer of electrons can move freely from ball to ball -- superconductivity. Add three more and it is an insulator again.
Intermediate doping gives intermediate effects: "You can dope them all the way from insulator to semiconductor to metallic conductor to superconductor: it really allows you to fine tune their properties," says DSIR superconductor expert Jeff Tallon.
The highest temperature for superconductivity in fullerides has been creeping up, from 18 Kelvin (Celsius degrees above absolute zero) in April last year, to 45 Kelvin in November. (Room temperature is about 290 Kelvin.)
It is possible that fullerides will have better mechanical properties than the present superconductors. To be useful, superconductors need to be formed into wires, and the present materials have tended to be crumbly.
One of the holy grails of chemistry has been a light and mouldable organic magnet, and fullerenes have promise there (but only up to 16 Kelvin so far).
Compounds of fullerenes open up other possibilities: buckyballs with a fluorine atom on every carbon, C60Fl60 -- "teflon balls" -- promise to be the world's best lubricants.
A film of C60 on a silicon base has proved to be an ideal substrate on which to grow a film of diamond. The uses of this can only begin to be imagined.
But it is the hollowness of fullerenes that leads to some of their most interesting properties. The C60 "cage" is big enough to hold a positively charged atom (an ion) of any of the common metals, and building them in is quite easy, shielding the world from some of their properties but leaving others, such as radioactivity, intact.