The chemical formula of titanium dioxide is TiO₂, which is mainly composed of titanium and oxygen. In its molecular structure, titanium atoms and oxygen atoms are covalently bonded to form a stable octahedral structure. 1. There are three main crystal structures of titanium dioxide: anatase, rutile and brookite, of which anatase and rutile are the two most common forms.

Crystal structure
Anatase: It has a tetragonal crystal structure, a high active surface, and strong photocatalytic activity. It is often used in photocatalysts and coatings for certain special purposes. It has high whiteness and strong light scattering ability, but its durability is not as good as rutile, its light resistance is poor, and it is obviously yellow when the temperature is higher than 400°C.

Rutile: It has a hexagonal crystal structure and is the most stable crystal form of titanium dioxide. It has high sun resistance, weather resistance and chemical stability, high melting point, higher density, hardness and dielectric constant than anatase, and higher refractive index, which can provide better hiding power and gloss, and is suitable for outdoor use and products under special climatic conditions.

‌Brookite type‌: It is relatively rare and usually exists in mineral form in nature.