Mixed and partial oxidation states. Photoelectron spectroscopic evidence

X-ray photoelectron spectra of the single valence platinum complexes K₂Pt(CN)₄] · 3H₂O(1),K₂Pt(CN)₄]Cl_0.3 · n H₂O(2) and K₂Pt(CN)₄]Cl₂ · 3H₂O(3) and the mixed valence compound Pt^II(C₂H₅NH₂)₄]Cl₄ · Pt^IV (C₂H₅NH₂)₄Cl₂] · 4H₂O(4) have been measured. It is found that one can distinguish clearly between mixed and single valence compounds by electron spectroscopy. The Pt spectrum of (4) is a superposition of a Pt^II and Pt_IV spectrum. The chemical shift between (1) and (3) is normal, however (2) shows an anomalous low binding energy for the Pt 4f electrons. The importance of using reliable reference peaks for obtaining absolute binding energies is emphasized.