These rules led to the structure of brookite ( 1928 ) and an understanding of the relative stability of the rutile, brookite and anatase forms of titanium dioxide.
12.
"' Brookite "'is the cell volume than either anatase or rutile, with 8 TiO 2 groups per unit cell, compared with 4 for anatase and 2 for rutile.
13.
Titanium is found in the Earth's crust only in the form of an ore, usually a titanium oxide, such as anatase, brookite etc . Titanium is extracted from titanium ore by removing the oxygen and reacting the ore with chlorine.
14.
Titanium dioxide has eight modifications in addition to rutile, anatase, and brookite, three metastable phases can be produced synthetically ( tetragonal and orthorombic ), and five high-pressure forms ( ?-PbO 2-like, baddeleyite-like, cotunnite-like, orthorhombic OI, and cubic phases ) also exist: