Information on the bonding states of the compositional atoms and on the occupied energy states of the Pd-3 (PS4)(2) crystals have been obtained by investigating the Pd 3d. and P and. S 2p core levels and the valence band region with the x-ray photoemission spectroscopy. In particular, as far as core levels are concerned, each XPS spectrum, apart from the spin-orbit splitting, exhibits a single-peak structure suggesting the absence of nonequivalent sites for the compositional atoms. The analysis of the chemical shifts in the core-level binding energies of the constituents emphasizes their cation or anion-type behavior. As to the valence band (VB) XPS spectrum, two regions are distinguished and interpreted on the basis of the comparison with the VB XPS spectra of other palladium and (PS4)(3-) compounds and of some thiophosphates. Confirmation of an involvement of the Pd 4d in the bonding is also given by the analysis of the spectral shape of the x-ray induced Pd M45VV Auger transition. (C) 2003 American Vacuum Society.