Titanium Di Oxide (Tio2)
Titanium dioxide, also known as titanium(IV) oxide or titania, is the naturally occurring oxide of titanium, chemical formula TiO2. When used as a pigment, it is called titanium white, Pigment White 6, or CI 77891. Generally it comes in two different forms, rutile and anatase. It has a wide range of applications, from paint to sunscreen to food colouring. When used as a food colouring, it has E number E171.
Titanium dioxide occurs in nature as well-known minerals rutile, anatase and brookite, and additionally as two high pressure forms, a monoclinic baddeleyite-like form and an orthorhombic a-PbO2-like form, both found recently at the Ries crater in Bavaria. The most common form is rutile, which is also the equilibrium phase at all temperatures. The metastable anatase and brookite phases both convert to rutile upon heating. Rutile, anatase and brookite all contain six coordinated titanium.
Titanium dioxide has eight modifications – in addition to rutile, anatase and brookite there are three metastable forms produced synthetically (monoclinic, tetragonal and orthorombic), and five high pressure forms (a-PbO2-like, baddeleyite-like, cotunnite-like, orthorhombic OI, and cubic phases):