Architecture of the Ti(IV) Sites in TiAlPO-5 Determined Using Ti K-Edge X-ray Absorption and X-ray Emission Spectroscopies

X-ray absorption and emission spectroscopies, supported by quantum mechanical calculations, were used to determine the architecture of Ti(IV) sites in Ti aluminophosphate AlPO4-5. The chemical sensitivity of the K beta(2,5) X-ray emission lines of Ti was exploited to monitor its local environment, proving that it mainly substitutes P in the framework, with a not negligible fraction substituting Al. Local structure of the substituted sites was found to be considerably deformed with respect to the AlPO4-5 original framework.