Chemical: TiO2; titanium dioxide.
Crystal structure: Orthorhombic
MineralogyTitanium dioxide has 4 polymorphic forms:
Brookite: Orthorhombic.
Akaogiite: monoclinic.
Anatase: tetragonal.
Rutile: tetragonal.
Brookite is rare, with larger cell volume; photocatalytic activity.
Iron, tantalum and niobium are common impurities in brookite.