What is the Difference Between Rutile and Anatase Titanium Dioxide?

Rutile and anatase titanium dioxide (TiO₂) are two mineralogical forms of titanium dioxide, which differ in their appearance, crystal structure, thermal stability, and applications. The main differences between rutile and anatase titanium dioxide are:

1. Appearance: Anatase TiO₂ is colorless, while rutile TiO₂ is usually found in yellow or reddish-brown colors.
2. Crystal Structure: Both anatase and rutile TiO₂ nanoparticles have a crystal structure consisting of interconnected TiO₂ octahedra, but the degree of distortion of the octahedron is different between the two forms.
3. Thermal Stability: Rutile TiO₂ is more thermally stable, while anatase TiO₂ is stable at room temperature but can be converted to rutile at high temperatures.
4. Diffraction Angles: The diffraction angle of anatase TiO₂ is located at 25.5°, while the diffraction angle of rutile TiO₂ is located at 27.5°.
5. Crystal Morphology: Rutile TiO₂ crystals are elongated, prismatic, and usually twinned, while anatase TiO₂ crystals typically have an octahedral shape.
6. Applications: Rutile TiO₂ is primarily used in the painting industry due to its bright color and high hiding power. It is also used in the production of high-quality water-based printing inks and plastic woodwork. On the other hand, anatase TiO₂ is mainly used in the textile and chemical fiber industries, as well as in printing inks, coatings, and cosmetics.

In summary, rutile and anatase titanium dioxide have distinct properties and applications, making them suitable for different industries and uses.

Comparative Table: Rutile vs Anatase Titanium Dioxide

Here is a table comparing the differences between Rutile and Anatase Titanium Dioxide:

Rutile Titanium Dioxide has a square (tetragonal) crystal system, a higher relative density, lower refractive index, and higher Mohs hardness compared to Anatase Titanium Dioxide. Rutile is optically positive and has a deep red color, while Anatase is optically negative and has a yellow to blue color. Rutile is used in high-end products and various applications, while Anatase is more suited for indoor applications and offers self-cleaning properties when exposed to UV rays.