titaniumIV

Titanium(IV) refers to titanium in its +4 oxidation state, the most common oxidation state for titanium in inorganic and organometallic compounds. Ti4+ has a d0 electronic configuration, is typically a hard Lewis acid, highly charge-dense, and is usually diamagnetic. In aqueous environments Ti4+ hydrolyzes readily, forming oxo- and hydroxo-bridged species and, at modest pH, colloidal TiO2·nH2O.

Among well-known Ti(IV) compounds are titanium tetrachloride (TiCl4), a volatile, moisture-sensitive liquid that hydrolyzes with water to give TiO2 and HCl and is used as a Lewis acid catalyst in polymerization. Titanum(IV) alkoxides, such as Ti(OR)4, are common precursors for sol–gel synthesis of titanium dioxide materials. In aqueous or alcohol solutions, Ti(IV) compounds form oxo- and hydroxo- complexes with various ligands, reflecting the high charge density of Ti4+.

Titanium dioxide (TiO2) is the principal Ti(IV) oxide. It exists as rutile, anatase, and brookite, with rutile and anatase being the most common forms. TiO2 is widely used as a white pigment in paints, coatings, plastics, and inks due to its brightness and refractive index, and also serves as a photocatalyst for environmental and energy applications under UV light. In catalysis and materials science, Ti(IV) centers are valued for their strong Lewis acidity and ability to form Ti–O bonds, enabling a range of reactions from polymerization catalysts to sol–gel derived oxide materials and thin films for photovoltaics and self-cleaning surfaces.

Safety and handling: TiCl4 fumes are corrosive; TiO2 is generally considered low-toxicity as a pigment but respirable dust can be hazardous; proper handling and disposal are required.