Valence band photoelectron spectra of platinum cyanides

Valence band X-ray photoelectron spectra of K₂Pt(CN)₄]·3H₂O (1), K₂Pt(CN)₄]Cl_0.3·xH₂O (2), and K₂Pt(CN)₄Cl₂]·3H₂O (3), and the ultraviolet photoelectron spectrum of (2) have been recorded. These spectra imply that the binding energy of the highest occupied molecular orbital (HOMO) in (1) is greater than in (2). A band-like character for the HOMO of (2) with finite electron density at the Fermi level is consistent with this observation. The photoelectron spectra are correlated with the solid state electronic absorption spectra. Shifts in the K 3 binding energies are attributed to considerable differences in lattice site potentials between (1) and (2).