Molecular Structures of Alumina Nanoballs and Nanotubes: A Theoretical Study

Molecular structures of alumina nanoballs and nanotubes have been determined. Tetrahedral, octahedral, and
icosahedral alumina nanostructures were derived from Platonic solids and Archimedean polyhedra and were optimized
by quantum chemical methods. Ih-symmetric balls, resembling their isovalence electronic analogues, fullerenes,
are preferred. The nanoballs consist of adjacent Al5O5 and Al6O6 rings, similar to C5- and C6-rings of fullerenes.
The structural characteristics of alumina nanoballs are dominated by π-electron donation from oxygen to aluminum.
Alumina nanotubes can be derived from icosahedral nanoballs. The tubes alternate between D5d- and D5h-symmetries
and are capped by halves of the icosahedral balls.