Physics and Chemistry of Spatially Resolved Microdomains in SbCl5-Intercalated Graphite

We report on the first spatially resolved study of the chemical and electronic properties of microdomains in molecular monolayers. Analytical electron-microscope measurements of stage-4 Sb${\mathrm{Cl}}_5$-intercalated graphite show Sb-rich islands of lateral dimension 500-1000 Å. Energy-loss spectra yield a 6-eV graphite $\pi$ plasmon modulated by the domain structure, but the 25-eV $\pi +\sigma$ plasmon and the carbon core excitations are spatially invariant. The derived island and background compositions are ${\left(\mathrm{Sb}{\mathrm{Cl}}_3\right)}_{\frac{1}{8}}{\left(\mathrm{Sb}{\mathrm{Cl}}_4^{-}\right)}_{\frac{1}{32}}$ and ${\left(\mathrm{Sb}{\mathrm{Cl}}_5\right)}_{\frac{9}{16}}{\left(\mathrm{Sb}{\mathrm{Cl}}_6^{-}\right)}_{\frac{9}{32}}$.