The charge transfer induced lithiation of single-wall carbon nanotubes (SWNTs) was investigated by in situ monitoring by Raman spectroscopy as lithium was added incrementally to a dispersion of SWNTs in liquid ammonia. Charge transfer from liquid ammonia solvated lithium to the SWNTs led to intercalation of lithium into the SWNT ropes, as well as to the semi-covalent lithiation of the SWNTs. Raman spectra of the SWNTs recorded as lithium was added showed a similar to 30 wavenumber downshift of the G band (1594 cm(-1)) with the concomitant appearance of a new peak at 1350 cm-1 that was assigned as the signature of the lithiated SWNTs. Addition of 1-iodododecane to the lithiated SWNTs resulted in the covalent attachment of dodecyl groups. The inter-calation of lithium throughout the SWNT ropes led to complete dodecylation of all individual SWNTs. (c) 2005 Elsevier B.V. All rights reserved.