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Titanium dioxide or Titanium(IV)oxide (TiO2, Molecular Weight 79.88) CAS no. 13463-67-7.

 

Natural titanium dioxide exists in nature in one of three crystalline forms, the two most important of which are anatase (CAS no. 1317-70-0) and rutile (CAS no. 1317-80-2), the third being brookite (12188-41-9). Rutile is the thermodynamically stable form of titanium dioxide; anatase rapidly transforms to rutile above 700°C.

 

Melting point: 1560°C (anatase), 1843°C (rutile), 1825°C (brookite)

Relative density: 3.9 (anatase), 4.26 (rutile), 4.17 (brookite)

The following definitions are applicable to the different titanium dioxide grades:

Pigmentary titanium dioxide is composed of primary particles with a mean particle size typically in the range 0.2 to 0.3 microns in diameter.

Nano titanium dioxide is composed of primary particles which are <100 nm in size. These primary particles naturally form aggregates and agglomerates which are above 100 nm.