The interaction between commercially available Single-Walled Carbon Nanotubes (SWNTs) and gaseous hydrazoic acid (HN3) was studied using attenuated total reflectance FTIR spectroscopy. Whether the HN3 gas reacts with SWNTs through physisorption or chemisorption was analyzed. This study shows that under ambient conditions gaseous HN3 reacted with the metal such as Ni or Fe present in the SWNTs to generate the corresponding metal azides. The data also suggest that the nanotube walls did not react to gaseous HN3 upon repeated exposures at ambient conditions. Published by Elsevier B.V.