Titanium dioxide, also known as titania, is a compound with the formula TiO2. It is a widely used industrial material that has a wide range of applications. It is typically white in color, but can be made in various shades by controlling the particle size and doping with other materials. Titanium dioxide is widely used in paints, coatings, cosmetics, and toothpaste, where it provides opacity and UV protection. It is also used in photovoltaic cells, as a catalyst for chemical reactions, and in some medical applications.