The synthesis of helically coiled nanotubes and nanowires through the use of In and Sn catalysts, respectively, in a floating-catalyst-based CVD process, is demonstrated. The figure is a scanning electron microscopy image of helically coiled carbon nanowires prepared from a thermal decomposition of xylene and acetylene in the presence of Fe-Sn catalyst particles. The bright spot at the tip of each nanowire represents the catalyst particle.