titaniedioxide

Titanium dioxide, TiO2, is a widely used white inorganic compound employed as a pigment and functional additive. The term titaniedioxide is sometimes encountered as a misspelling; the standard name is titanium dioxide. It occurs naturally in minerals such as rutile, anatase, and brookite, with rutile being the most stable form at high temperatures. TiO2 has a high refractive index and strong opacity, giving brightness and whiteness to many products. The material exists mainly in two crystalline forms used commercially: rutile and anatase.

Industrial production of pigment-grade TiO2 is dominated by two processes: the sulfate process and the chloride process. The sulfate process extracts TiO2 from precursor ores using sulfuric acid, while the chloride process converts titanium tetrachloride to TiO2 and generally yields higher-purity rutile pigment. Particle size is tailored by grade: standard pigment TiO2 is in the submicrometer range to provide opacity, whereas ultrafine or nanoparticulate TiO2 finds use in cosmetics and certain coatings and applications.

Common applications include as a white pigment in paints, coatings, plastics, and paper; as a UV filter in sunscreens and cosmetics; and as a photocatalyst for environmental purification and self-cleaning surfaces. TiO2 also plays a role in electronics and energy-related applications where light interaction is important.

Safety and regulation: TiO2 is of low acute toxicity by ingestion. Inhalation of TiO2-containing aerosols has been classified by IARC as possibly carcinogenic to humans (Group 2B) for certain exposure conditions, leading to regulatory scrutiny in some jurisdictions. Regulations vary by region and by product form; some uses, such as food additives, have been restricted or banned in certain markets, particularly for nanoparticulate forms.