Bucky Onion (Molecule of the Month for December 2005)
Nested Fullerene, buckyonion, c540, c240, c60
The discovery of buckyballs (C60) which has a nanometer-scale hollow spherical structure in 1985 by Kroto and Smalley revealed a new form of existence of carbon element other thab graphite, diamond and amorphous carbon. In a further development of the study of carbons structures, 1991, Iijima discovered carbon nanotubes in carbon soot, which can be described as a seamless tube formed by the curling of hexagonal graphite sheets. Carbon nanotubes can be classed as single-wall nanotubes and multi-wall nanotubes, with the former further grouped into armchair, zigzag and chiral structures, depending on the angle and the length of the chiral vector.
Whilst Iijima was using very powerful microscopes (Transmission Electron Micrscope - TEM) to look for carbon nanotubes he observed C60 structures and multi-layered spherical structures - bucky onions!
Further experiments by scientists around the world discovered these spherical structure may have as many as 70 layers each with a interlayer distance matching that of bulk graphite. Since then it has been established that the fabrication of the nanotubes is usually accompanied by the generation of bucky onions.
Formal Chemical Name (IUPAC)
Update by Karl Harrison
(Molecule of the Month for December 2005 )