Ab initio self-consistent X-ray absorption near-edge structure (XANES) calculations for the Pt L-3 edge of (NH4)(2)PtCl4 and K2PtCl6 are in good agreement with experiment. These results allow us to assign a notable postedge XANES feature as a 'hybridization peak', i.e., a mixture between the photoelectron state and unoccupied, atomic Cl 3d-states, mediated by multiple-scattering An analogous interpretation applies to certain 'pre-edge' peaks. A characteristic of such peaks is their approximate energy independence, in contrast to X-ray absorption fine-structure peaks. For Pt-Cl compounds, this suggests a way of monitoring the number of neighboring atoms in chemical processes using XANES.