Well graphitized nanocarbons including onion-like fullerenes and multi-walled carbon nanotubes were synthesized in high yield by arc discharge in water between pure graphite electrodes. Onion-like fullerenes were obtained as the floating powders on the water surface and multi-walled carbon nanotubes were found at the bottom of the container. Field emission scanning electron microscopy, high-resolution transmission electron microscopy and X-ray diffraction were employed to study the crystallography of these carbon nanostructures. The results indicated that both onion-like fullerenes and multi-walled nanotubes synthesized at the current of 50 A were of the best quality. (c) 2007 Published by Elsevier B.V.