Brookite is the orthorhombic variant of titanium dioxide , TiO2, which occurs in many natural polymorphic forms (minerals with the same composition but different structure). The International Mineralogical Association (IMA) recognizes four forms; the others are akaogiite), anatase) and rutile ). Brookite is rare compared to anatase and rutile and, like these forms, it exhibits photocatalytic Brookite has a larger cell volume than either anatase or rutile, with 8 TiO2 groups per unit cell, compared with 4 for anatase and 2 for rutile. Ta and niobium
It was named in 1825 by French mineralogist Armand Lévy for Henry James Brooke (1771–1857), an English crystallographer, mineralogist and wool trader.
Arkansite , US, that is also found in the Murunskii Massif , in the Aldan Shield , Russia, where many other unusual minerals occur.
At temperatures above about 750 °C, brookite will revert to the rutile structure.