In addition to the changes in the ν(O-W-O) modes , the lower frequency Raman peak corresponding to the δ(O-W-O) mode decreases in intensity and broadens. The film reduced in TBA + electrolyte shows only minimal broadening, furthering our hypothesis that the structural changes are the result of cation intercalation. The last major difference is in the higher frequency peaks related to the ν(W=O) modes. This double bond stretching mode has been assigned to terminal tungsten oxygen occurring both for tungsten ions near oxygen vacancies and due to surface termination of the tungsten octahedra. Both of these structural motifs are plausible contributors for our samples, considering the high surface area of nanocrystalline materials and the prevalence of oxygen deficiencies in various tungsten oxide phases. The ν(W=O) modes shift to lower frequency in all reduced samples relative to the pristine sample, which could be related to the reduction of tungsten cations in the material. Reduction of tungsten to lower oxidation states cause an increase in W-O bond length and softening of that bond, due to the lower charge of the tungsten. The structural changes observed for Li + and Na + intercalated films are consistent with our hypothesis that the insertion of these cations into the material results in more significant charge localization associated with polaronic states.