Fig. 2
From: A highly reactive precursor in the iron sulfide system
Raman and XPS data of FeSnano. a Raman spectrum and deconvolutions of bands in FeSnano showing the asymmetric (204 and 215 cm−1) and symmetric (274 cm−1) Fe–S vibrations and various polysulfide species. Peaks marked with (*) are from the silicon grease from the sample holder. The asymmetric Fe–S vibrations at 204 and 215 cm−1, with full width at half maximum (FWHM) of 15 and 9 cm−1, respectively, correspond to monosulfides; b–d XPS spectra from FeSnano showing in b S2p with the doublet corresponding to the split of the spin-orbit into S2p3/2 and S2p1/2 in c Fe2p with fitting performed using the 2p3/2 envelope and in d O1s high-resolution XPS spectra and fits for the FeSnano phase revealing the lack of Fe–O or S–O species; e–g corresponding to S2p, Fe2p, and O1s high-resolution XPS spectra from FeSnano after argon etching for five times 1 min. The XPS data indicate that sulfur atoms in FeSnano were present in two slightly different chemical environments (i.e., binding energies of 161.1 and 161.8 eV; Supplementary Table 6), that could reflect the presence of different atomic coordination arrangements47. The Fe and S species remained unchanged after etching; however, the relative contributions of the species after etching changed slightly, in particular for the S species (Supplementary Table 6). a.u. arbitrary unit
