High yields of dense, 'clean' and uniform arrays of well-aligned carbon nanotubes, with bamboo-like structure encapsulating gaseous nitrogen, were obtained by thermolyzing uniform aerosols of ferrocene/benzylamine solutions at 850 degreesC. Electron energy loss spectroscopy (EELS) studies reveal that up to 90% of these tubes contain molecular nitrogen in their cores. The materials were characterized by scanning electron microscopy, X-ray powder diffraction, high-resolution transmission electron microscopy, and EELS elemental mappings using an Omega Filter microscope. We envisage the material useful for storing large concentrations of relatively heavy gases such as nitrogen in confined volumes. (C) 2004 Elsevier B.V. All rights reserved.