Why Some Bucky Tubes Would be Metallic?

Abstract
As a reply to the title question, it has been elucidated that metallic bucky tubes are equivalent to those involving plural numbers of isolated polyacetylene (PA) skeletons (cis-type) arranged either in a helical or non-helical manner on the tube surface. Such helical PA skeletons guarantee the metallic conduction path to the electrons near the Fermi level (spiralons). Control of the flow of these spiralons may open up a stage for nano-technology of the electronic devices such as molecular solenoid applicable to molecular electromagnet, molecular electric generator and so on.