In (A), the peaks on the low binding energy side (yellow) are attributed to sulfide S 2-or thiolate t BuS -, and the peaks on the high binding energy side (green) are attributed to S derived from sulfonate t BuSO3 -. Spectrum (B) indicates that the charge state of I is similar to that of I -. Spectrum (C) indicates that X@Ag54 does not include Cu. In (D), the peaks around 368 eV and 374 eV are attributed to Ag 3d5/2 and Ag 3d3/2, respectively. These spectra indicated that the oxidation state of Ag in X@Ag54 was similar to that of Ag2S and AgO.