New insights for titanium(iv) speciation in acidic media based on UV-visible and 31 P NMR spectroscopies and molecular modeling

Titanium chemistry in aqueous acidic media has been extensively investigated over the last decades. Hydrolyzed species such as Ti(OH) , TiO , Ti(OH) or Ti(OH) have been identified and their equilibria have been studied in nitric and perchloric acid. A predominance of the divalent cations was found for low pH ( , pH 0.1 mol L ), as stable precursors for the formation of condensed titanium dioxide. The present paper reconsiders firstly previous knowledge about the speciation of titanium(iv) in non-complexing acidic media by giving evidence for the presence of polynuclear hydrolyzed species, even at very low Ti(iv) concentration ( , typically