‘‘White line’’ in the chlorine K x‐ray absorption spectra of K2PdCl4, K2PtCl4, K2PdCl6, and K2PtCl6

The chlorine K absorption spectra from complex compounds K2PdCl4, K2PtCl4, K2PdCl6, and K2PtCl6 have been obtained with a 50 cm bent‐quartz crystal vacuum spectrograph. An intense ‘‘white line’’ has been found at the absorption threshold and shows the chemical shift which is closely related with the ionization potentials of Pd and Pt, corresponding to the transition from the chlorine 1s level to the lowest unoccupied antibonding orbital originating from the Pd 4d or Pt 5d and Cl 3p orbitals. The other absorption structures are alike throughout four compounds. A tentative explanation for the absorption structures near the K edge is made in terms of the core level‐to‐empty state transitions in the Cl− ion. Radiation effect is found on the chlorine K absorption spectrum of K2PdCl6.