  Mixed-valence compound Pb3O4 (minium) has been studied using X-ray absorption
near-edge structure (XANES) spectroscopy and DFT calculations. In spite of
presence of two valence states of lead [Pb(II) and Pb(IV)], the XANES spectrum
of studied system is corresponding to apparently unified, an intermediate
valence state of Pb. On the other hand, the 207Pb NMR spectra definitely show
two different spectral bands corresponding to different Pb2+ and Pb4+ ions in
Pb3O4 crystal structure. The explanation of this contradiction is related to
the basics of XANES and NMR spectroscopy.
