Titanium dioxide



         


</table> Titanium dioxide, also known as titania is the naturally occurring oxide of titanium, chemical formula TiO2. Pure titanium dioxide does not occur in nature but is derived from ilmenite or leuxocene ores. It is also readily mined in one of the purest forms, rutile beach sand. An important use of titanium dioxide is in powder form as a pigment for providing whiteness and opacity to such products such as paints and coatings but also plastics, paper, inks, food and cosmetics, including most toothpastes. Titanium dioxide is by far the most widely used white pigment, it is very white and has a very high refractive index (n=2.4) — only surpassed by diamond. The high refractive index and bright white colour of titanium dioxide make it an effective opacifier for pigments, and (when deposited as a thin film), as a reflective optical coating for dielectricmirrors. One of its other major advantages is its resistance to discoloration under UV light. The Vinland map, the map of America ("Vinland") that was supposedly drawn during mid-15th century based on data from the Viking Age, has been declared a forgery on the basis that the ink on it contains traces of the TiO2-form anatase; TiO2 was not synthetically produced before the 1920s. Recently (1992) a counter-claim has been made that the compound can be formed from ancient ink.
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Properties

General

Name Titanium (IV) oxide
Chemical formula TiO2
Appearance White solid

Physical

Formula weight 79.9 amu
Melting point ~2103 K (1830 °C)
Boiling point ~2773 K (2500 °C)
Density 4.2 ×103 kg/m3
Crystal structure rutile
Solubility insoluble

Thermochemistry

ΔfH0gas -249 kJ/mol
ΔfH0liquid -879 kJ/mol
ΔfH0solid -944 kJ/mol
S0solid 51 J/mol·K

Safety

Ingestion Low hazard for accidental ingestion.
Inhalation Irritating, dangerous in the long term.
Skin Low hazard.
Eyes Low hazard.
More info

SI units were used where possible. Unless otherwise stated, standard conditions were used.

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