A heterogeneous catalyst for hydrochlorination of acetylene by gas-phase HCl is formed as a result of mechanical treatment of the solid salt K2PtCl6 under an acetylene, ethylene, or propylene atmosphere. We used X-ray photoelectron spectroscopy (XPS) to prove that under these conditions, in the near-surface layers of the K2PtCl6 matrix, there was formation of Pt(II) complexes and platinum complexes with vacancies in the coordination sphere. We hypothesized that the active centers of the catalyst are defects in the K2PtCl6 lattice in the form of impurity platinum(II) ions in the K2PtCl6 matrix.