XPS investigation of titanium in melanites from Monte Vulture (Italy)

X-ray photoelectron spectroscopy has been used to study the oxidation state and structural role of titanium in two melanites differing in TiO (sub 2) content ( approximately 3 and approximately 6 wt.%). The Ti2p-XPS spectra can be satisfactorily fitted when Ti (super 3+) is lodged on octahedral and Ti (super 4+) distributed over octahedral and tetrahedral sites. The XPS direct estimates of Ti site populations match well with those obtained indirectly from Moessbauer spectroscopy through the Fe distribution. In addition, there is good agreement between the Fe (super 2+) /Fe (super 3+) ratios estimated by both XPS and Moessbauer spectroscopy, using Fe (sub 3) O (sub 4) as a standard for interpreting Fe2p photoelectron spectra.