The effect of atomic nitrogen, generated by a radio frequency plasma source, on clean InSb(001) at 275 degrees C has been studied using x-ray photoelectron spectroscopy (XPS) and resonant Raman scattering (RRS). Chemically shifted XPS features of the Sb 3d region revealed the formation of a reacted Sb species. This reacted Sb was unambiguously identified as mainly Sb-N by comparison with results from as deposited and nitrided, thick elemental Sb layers on InSb. The Sb 3d feature due to this Sb-N species was found to have a chemical shift of 1.65+/-0.10 eV to higher binding energy compared with the InSb peak, while for the elemental Sb the shift was only 0.45+/-0.10 eV in the same direction. Although not obvious from the XPS data the RRS spectra of a much longer nitridation at 275 degrees C showed the presence of crystalline elemental Sb. Annealing studies of elemental Sb and nitrided Sb layers showed the Sb-N species to be significantly less volatile than elemental Sb.