|The Surprising Appearance of Nanotubular Fullerene D5h(1)-C90|
The previously undetected fullerene D5h(1)-C90—with a distinct
nanotubular shape—has been isolated as the major C90 isomer
produced from Sm2O3-doped graphite rods and structurally
identified by single-crystal x-ray diffraction. Fullerenes are
well-defined molecules that consist of closed cages of carbon
atoms and distinct inside and outside surfaces. They tend to
form very small crystals; consequently, high-resolution data was
collected using small-molecule crystallography at ALS Beamline
11.3.1. The discovery of nanotubular D5h(1)-C90, which is a
fullerene with 90 carbon atoms and D5h symmetry, opens a bridge
between molecular fullerenes and carbon nanotubes. In recent
years, the well-known solid allotropes diamond and graphite have
been joined by new allotropes: fullerenes, carbon nanotubes, and
graphene. Diamond consists of four-coordinate carbon atoms with
tetrahedral geometry, while the other allotropes involve three-
coordinate carbon atoms.