Titanium dioxide (TiO₂). Titanium dioxide is the most common white pigment used today. As a pigment, titanium dioxide is unique because it combines both high colouring and high opacifying capacity. This is mainly due to its high refractive index (2.7). Furthermore, titanium dioxide is an excellent UV absorber (it is used in sun protective creams). Some typical properties are: density 3.3-4.25 g/cm³; pH of water suspension 3.5-10.5; particle size 8–300 nm; oil absorption 10–45 g/100 g; specific surface area 7–160 m²/g. Most titanium dioxide is produced from the rutile (TiO₂) or ilmenite (titanate of ferrous iron). Titanium dioxide can be obtained using different processes.

Manufacturers get titanium dioxide from minerals called brookite, rutile, and anatase. It's processed into a powder and refined to meet strict safety guidelines.

This article was written by Kamilah Guiden and reviewed by Megan Meyer, PhD.

This cytotoxic effect was also reported before; i.e. Natarajan et al. conducted an experiment that found a strong oxidative stress, morphological changes in mitochondria and substantial loss in the fusion of primary hepatocytes exposed to P25TiO₂NPs [52].