The (6,5) single-wall carbon nanotubes have been preferentially synthesized from a one-dimensional array of C(60) inside single-wall carbon nanotubes (d≅ 1.5 ± 0.1 nm). The as-produced inner tubes have been extracted via sonication and density gradient ultracentrifugation methods and demonstrated to be dominated by (6,5) tubes by optical absorption, Raman scattering, photoluminescence, high-resolution transmission electron microscope observation, and a semi-empirical simulation (PM3).