Nanobamboo and nanotube structures of BN have been controllably synthesized by reaction of barium metaborate with ammonia. The gallium addition plays an important role in the formation of nanotubes. The experimental results indicate that, without the gallium additive, the reaction results in the growth of nanobamboo structure. Gallium addition, probably as a catalyst within the framework of vapor-liquid-solid growth, promotes the growth of nanotubes. High-solution transmission electron microscopy research indicates that rhombohedral stacking order is the dominant atomic arrangement for BN nanobamboos; whereas hexagonal stacking is the dominant arrangement for BN nanotubes. (C) 2003 Elsevier Science B.V. All rights reserved.