Difference between revisions of "Rutile"

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(Other polymorphs of (TiO2): added tistarite)
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== Other polymorphs of (TiO<sub>2</sub>) ==
 
== Other polymorphs of (TiO<sub>2</sub>) ==
  
Another polymorph of (TiO<sub>2</sub>) is [[anatase]] (mohs 5.5 to 6.0). <br>
+
[[anatase]] (Mohs 5.5 to 6.0). <br>
 
It also has a simple tetragonal crystal lattice but different from the rutile structure
 
It also has a simple tetragonal crystal lattice but different from the rutile structure
in that the unit cell is a bit bigger.
+
in that the unit cell is a bit bigger (and sparser?).
  
A third polymorph of (TiO<sub>2</sub>) is [[brookite]] (mohs 5.5 to 6.0). <br>
+
[[brookite]] (Mohs 5.5 to 6.0). <br>
 
It also has a bigger unit cell than rutile and has the lower orthorombic crystal structure symmetry
 
It also has a bigger unit cell than rutile and has the lower orthorombic crystal structure symmetry
which may make it a bit less interesting as a potential base material.
+
which perhaps may make it a bit less interesting as a potential base material.
 +
 
 +
[[tistarite]] ('''Mohs 8.5'''). <br>
 +
Trigonal crystal structure.
  
 
== Misc ==
 
== Misc ==

Revision as of 07:46, 24 June 2021

Rutile is a polymorph of titanium dioxide (TiO2)
It may be of peculiar interest because:

  • it contains the element titanium (Ti) whitch is one of the more abundant elements in earth crust.
  • it has a reasonably high hardness (Mohs 6.0 to 6.5)
  • it features a reasonably simple (tetragonal) crystal lattice (in fact it's the defining minearal for the rutile structure)
  • with the rutile structure it features the exact same structure as stishovite (a peculiarly interesting SiO2 polymorph) but given it occurs naturally in high quantities (unlike stishovite) it likely has a higher thermodynamic stability. That is: it's less prone to diffusion into a more stable polymorph at higher temperatures.

Given both rutile and stishovite feature the same crystal structure it may be possible to mechanosynthesize checkerboard neo-polymorphic transitions by replacing some Ti with with Si in a regular pattern.

Other polymorphs of (TiO2)

anatase (Mohs 5.5 to 6.0).
It also has a simple tetragonal crystal lattice but different from the rutile structure in that the unit cell is a bit bigger (and sparser?).

brookite (Mohs 5.5 to 6.0).
It also has a bigger unit cell than rutile and has the lower orthorombic crystal structure symmetry which perhaps may make it a bit less interesting as a potential base material.

tistarite (Mohs 8.5).
Trigonal crystal structure.

Misc

  • All (TiO2) polymorphs have a high refractive index

Potential elements for controlled mechanosynthetic substitution for doping or the creation of neo-polymorphs include:

  • iron Fe (extremely common) – a common natural impurity of rutile
  • niobium Nb (less common) – a common natural impurity of rutile
  • tantalum Ta (extremely rare) – a common natural impurity of rutile
  • possibly silicon Si – since it forms an oxide with exactly the same crystal structure as rutile (stishovite)

Elements that also shares the rutile structure:

  • the germanium dioxide mineral argutite (wikipedia) (germanium is one of the more rare elements though)
  • the tin dioxide minearl cassiereite (wikipedia) (tin is a bit more common than germanium)
  • ...

Interplanetary applications (Moon)

Titanium is supposedly especially abundant on the moon.
So future gem-gum products on the moon may feature a lot of rutile, anatase, brookite, (or other titanium based gemstones) for structural parts.

Related

The emenets in the Silicon group like to kake on rutile structure too.
A lot of neo-polymorphs may become possible by swapping out some of the titan for other compatible elements.

External links