Stishotile: Difference between revisions
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{{Site specific term}} | {{Site specific term}} | ||
This is not an official name. <br> | This is not an official name. <br> | ||
It is a portmanteau out of some self suggesting options: | |||
* Stishotile/Stishutile (emphasizing the ultra-hard SiO<sub>2</sub> endmember) | |||
* Ruthovite (emphasizing the more widely known rutile endmember, hinting more obviously at the structure) | |||
* Mechandensite ※ | |||
※ One end-member is a the '''super-dense SiO<sub>2</sub> polymorph''' stishovite <br> | |||
and it should me a good material for '''mechanical applications'''. <br> | |||
So mechadensite seems fitting from a possible name. <br> | |||
Plus mechadense is this wikis [[author]]s primary internet pseudonym. <br> | |||
Would be nice to get my name on a novel gem-like material (very likely first time introduced here). Just a suggestion. <br> | |||
Side-note süssite/suessite already exists F<sub>3</sub>Si Mohs 5.75 bcc <br> | |||
Given the dominance of iron and the semi-metallic silicon this likely has intermetallic compound properties. <br> | |||
<small>Hans Eduard Suess also an Austrian but not blood-related to [[APM:About|this wikis author]] sharing same family name. </small> | |||
== Stoichometry and examples == | == Stoichometry and examples == | ||
'''The | '''The stishotile series:''' | ||
* General formula: Si<sub>x</sub>Ti<sub>y</sub>O<sub>z</sub> <br>2*(x+y)=z | * General formula: Si<sub>x</sub>Ti<sub>y</sub>O<sub>z</sub> <br>2*(x+y)=z | ||
'''Examples:''' | '''Examples:''' | ||
* SiTiO<sub>4</sub> (equistoicometric | * SiTiO<sub>4</sub> (equistoicometric stishotile) | ||
* Si<sub>3</sub>TiO<sub>8</sub> (silicon leaning | * Si<sub>3</sub>TiO<sub>8</sub> (silicon leaning stishotile – presumably more hardness and less thermal stability) | ||
'''End members are:''' | '''End members are:''' | ||
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[[Germanium]] Ge and [[lead]] Pb from group 14 may be suitable when added in sparingly. <br> | [[Germanium]] Ge and [[lead]] Pb from group 14 may be suitable when added in sparingly. <br> | ||
And maybe even [[zirconium]] Zr and [[hafnium]] Hf (very rare element) being chemically similar to [[titanium]] Ti. | And maybe even [[zirconium]] Zr and [[hafnium]] Hf (very rare element) being chemically similar to [[titanium]] Ti. | ||
Alternate naming? | |||
== Likely propertiers == | == Likely propertiers == | ||
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'''A "mixing series" may allow for combining the advantages of both''' by <br> | '''A "mixing series" may allow for combining the advantages of both''' by <br> | ||
tuning the Si/Ti ratio such that the material attains both high mechanical and high thermal stability. | tuning the Si/Ti ratio such that the material attains both high mechanical and high thermal stability. | ||
== Other [[neo-polymorph]]ic checkerboard mixing series with same elements but different structure == | |||
[[Seifertite]] the second ultra-dense ultra-hard common quartz SiO2 polymorph. <br> | |||
is isostructural to the stable mineral [[Scrutinyite]] (Mohs ??, density 9.867g/ccm) <br> | |||
But there's evidence for stability of titanium and tin variants too. <br> | |||
== Related == | == Related == | ||
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* [[Dialondeite]] | * [[Dialondeite]] | ||
---- | ---- | ||
Other potential '''[[neo-polymorph]]''' series | Other potential '''[[neo-polymorph]]''': The [[titanosapphire]] series from [[leukosapphire]] to [[tistarite]] | ||
* [[Deltalumite]] | |||
== External links == | |||
* https://en.wikipedia.org/wiki/Stishovite | |||
* https://en.wikipedia.org/wiki/Rutile | |||
---- | |||
* https://en.wikipedia.org/wiki/Suessite | |||
* https://www.mineralienatlas.de/lexikon/index.php/MineralData?mineral=Suessit | |||
Latest revision as of 08:22, 23 September 2025
This is not an official name.
It is a portmanteau out of some self suggesting options:
- Stishotile/Stishutile (emphasizing the ultra-hard SiO2 endmember)
- Ruthovite (emphasizing the more widely known rutile endmember, hinting more obviously at the structure)
- Mechandensite ※
※ One end-member is a the super-dense SiO2 polymorph stishovite
and it should me a good material for mechanical applications.
So mechadensite seems fitting from a possible name.
Plus mechadense is this wikis authors primary internet pseudonym.
Would be nice to get my name on a novel gem-like material (very likely first time introduced here). Just a suggestion.
Side-note süssite/suessite already exists F3Si Mohs 5.75 bcc
Given the dominance of iron and the semi-metallic silicon this likely has intermetallic compound properties.
Hans Eduard Suess also an Austrian but not blood-related to this wikis author sharing same family name.
Stoichometry and examples
The stishotile series:
- General formula: SixTiyOz
2*(x+y)=z
Examples:
- SiTiO4 (equistoicometric stishotile)
- Si3TiO8 (silicon leaning stishotile – presumably more hardness and less thermal stability)
End members are:
- rutile TiO2 and
- stishovite SiO2 (isostructural to rutile thus not quartz).
Other compatible elements (mainly tin)
There is also cassierite a hard stable tin oxide minearal in rutile structure (isostructural).
While cassiertite is a bit harder than rutile tin is a much less abundant element than titanium also it is notably heavier.
- Rutile: Mohs 6.0–6.5 density 4.23g/ccm
- Cassierite: Mohs 6.0-7.0 density 6.98–7.1g/ccm
General formula for tin-mechadensites: SixSnyOz where 2*(x+y)=z
Germanium Ge and lead Pb from group 14 may be suitable when added in sparingly.
And maybe even zirconium Zr and hafnium Hf (very rare element) being chemically similar to titanium Ti.
Alternate naming?
Likely propertiers
- high hardness (Mohs 6 to Mohs 9)
- electrically non conductive wide band-gap
- optically transparent in visible spectral range
- strong optical dispersion
- high heat conductance (but far from diamond)
Not a solid solution mixing series
Regarding "mixing series" note that this is meant as a piezomechanosyntesized checkerboard compound.
It is not supposed to be a thermodynamic solid solution with statistically distributed (random) placement of atoms.
Such a solid solution might not even be accessible via thermodynamic production pathways,
that is melting mixing and recrystallizing (possibly under bulk pressure).
It should be quite easy to figure out which Ti/Si ratios allow for symmetric checkerboard patterns
with extended unit cells of minimal size.
What is so special about this gemstone? …
Rutile TiO₂ is limited in hardness (Mohs 6 to 6.5) but thermally highly stable.
Stishovite SiO₂ is ultra hard (Mohs 8.5 to 9) but likely thermally less stable since
it's a metastable high pressure modification of quartz (SiO₂ too).
A "mixing series" may allow for combining the advantages of both by
tuning the Si/Ti ratio such that the material attains both high mechanical and high thermal stability.
Other neo-polymorphic checkerboard mixing series with same elements but different structure
Seifertite the second ultra-dense ultra-hard common quartz SiO2 polymorph.
is isostructural to the stable mineral Scrutinyite (Mohs ??, density 9.867g/ccm)
But there's evidence for stability of titanium and tin variants too.
Related
End-members:
Not via thermodynamic equilibriom production.
No solid solutions:
Involved elements:
Another "checkerboard-mixing-series" with a here given name:
Other potential neo-polymorph: The titanosapphire series from leukosapphire to tistarite