The specific crystallographic features of Fe1/4TiS2 have led us to carry out an experimental (X-ray photoelectron spectroscopy) and theoretical (augmented spherical wave method) study to shed light on the different chemical environments of atoms in the structure and their host-guest interaction. The chemical shifts or/and broadening of the core-level peaks have been correlated with initial and final states, the former based on the charge transfer between the iron intercalant and the host titanium atoms. The valence band is modified by the intercalant, primarily towards low binding energies. The electronic structure calculations are in good agreement with the observed spectra. © 1997 Elsevier Science B.V.