Difference between revisions of "Salts of oxoacids"
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From Mg<sub>2</sub>SiO<sub>4</sub> forsterite to Fe<sub>2</sub>SiO<sub>4</sub> fayalite. <br> | From Mg<sub>2</sub>SiO<sub>4</sub> forsterite to Fe<sub>2</sub>SiO<sub>4</sub> fayalite. <br> | ||
And especially the associated high pressure modifications. <br> | And especially the associated high pressure modifications. <br> | ||
| − | '''High pressure modifications tend to have higher | + | '''High pressure modifications tend to have higher crystal symmetries and mechanical strength at the cots of a bit of thermal stability.''' |
| + | |||
| + | === Olivin/Peridot end-members and their low pressure stable stable high pressure modifications === | ||
Low pressure magnesium endmember forsterite: | Low pressure magnesium endmember forsterite: | ||
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High pressure modifications of fayalite: | High pressure modifications of fayalite: | ||
* γ-Fe<sub>2</sub>SiO<sub>4</sub> '''ahrensite''' – '''cubic''' – 4.85g/ccm – high pressure crystal structure of fayalite – [https://www.mineralienatlas.de/lexikon/index.php/MineralData?mineral=Ahrensite (de)] | * γ-Fe<sub>2</sub>SiO<sub>4</sub> '''ahrensite''' – '''cubic''' – 4.85g/ccm – high pressure crystal structure of fayalite – [https://www.mineralienatlas.de/lexikon/index.php/MineralData?mineral=Ahrensite (de)] | ||
| − | + | ||
| − | + | === Silicates of further rather common elements === | |
| − | + | ||
| + | '''Calcium:''' | ||
* γ-Ca<sub>2</sub>SiO<sub>4</sub> Calcio-Olivine – Mohs 4.5 – orthorhombic | * γ-Ca<sub>2</sub>SiO<sub>4</sub> Calcio-Olivine – Mohs 4.5 – orthorhombic | ||
* β-Ca<sub>2</sub>SiO<sub>4</sub> [https://en.wikipedia.org/wiki/Larnite Larnite] – Mohs 6 – monoclinic (?) | * β-Ca<sub>2</sub>SiO<sub>4</sub> [https://en.wikipedia.org/wiki/Larnite Larnite] – Mohs 6 – monoclinic (?) | ||
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Beyond that adding one more element there are an innumerable amount of natural silicates around. | Beyond that adding one more element there are an innumerable amount of natural silicates around. | ||
| + | |||
| + | === Some semi random picks of other silicates === | ||
Misc, Not exactly a salt but related ... | Misc, Not exactly a salt but related ... | ||
* PbCa<sub>3</sub>Zn<sub>4</sub>'''(SiO<sub>4</sub>)<sub>4</sub>''' esperite [https://en.wikipedia.org/wiki/Esperite] Mohs 5-5.5 (unabundant zinc | exceptionally hard lead mineral) Specific gravity: 4.28-4.42 | * PbCa<sub>3</sub>Zn<sub>4</sub>'''(SiO<sub>4</sub>)<sub>4</sub>''' esperite [https://en.wikipedia.org/wiki/Esperite] Mohs 5-5.5 (unabundant zinc | exceptionally hard lead mineral) Specific gravity: 4.28-4.42 | ||
---- | ---- | ||
| + | |||
| + | === Other pages listing silicates of interest === | ||
Context specific silicates are also listed on these pages: | Context specific silicates are also listed on these pages: | ||
Revision as of 10:44, 26 June 2021
The X-O-X bonds present in those compounds increase the space between the spacially linking X atoms. This lead to a lower density of bonds in cross sections inclusion of bigger voids thus higher porousity. Due to the porousness of these compounds it is harder to get the surfaces flat - figuratively like the surface of a pumice stone. It's impossible to get them as smooth as passivated diamond. [todo: investigate wheter superlubricating bearings can be constructed from these types of diamondoid compounds]
Contents
Silicates (& Quartz)
Silicates typically have pretty good mechanical properties.
Typically Mohs 5-6 sometimes up to almost ~8.
Of interest as base materials may be the pure end members of the mixing series of
olivine (wikipedia) / peridot (wikipedia)
From Mg2SiO4 forsterite to Fe2SiO4 fayalite.
And especially the associated high pressure modifications.
High pressure modifications tend to have higher crystal symmetries and mechanical strength at the cots of a bit of thermal stability.
Olivin/Peridot end-members and their low pressure stable stable high pressure modifications
Low pressure magnesium endmember forsterite:
- Mg2SiO4 Forsterite – orthorhombic dipyramidal – Mohs 7
High pressure modifications of fortserite:
- Mg2SiO4 wadseylite (wikipedia) – sorosilicate – ortorhombic – dipyramidal – Mohs ?? – mid pressure crystal structure
- Mg2SiO4 ringwoodite (wikipedia) – nesosilicate – cubic – Mohs ?? – 3.9g/ccm – high pressure crystal structure
Low pressure iron endmember fayalite:
High pressure modifications of fayalite:
- γ-Fe2SiO4 ahrensite – cubic – 4.85g/ccm – high pressure crystal structure of fayalite – (de)
Silicates of further rather common elements
Calcium:
- γ-Ca2SiO4 Calcio-Olivine – Mohs 4.5 – orthorhombic
- β-Ca2SiO4 Larnite – Mohs 6 – monoclinic (?)
- Ni2SiO4 Liebenbergite (de) – (Mohs 6-6.5 or 4.5?) -- orthorhombic
- Mn2SiO4 Tephroite (maybe less interesting since Mn is more scarce) – orthorhombic dipyramidal – Mohs 6
- TiSiO4 Titanium Silicate (no natural mineral here?) [1] (broken)
Beyond that adding one more element there are an innumerable amount of natural silicates around.
Some semi random picks of other silicates
Misc, Not exactly a salt but related ...
- PbCa3Zn4(SiO4)4 esperite [2] Mohs 5-5.5 (unabundant zinc | exceptionally hard lead mineral) Specific gravity: 4.28-4.42
Other pages listing silicates of interest
Context specific silicates are also listed on these pages:
- Ternary and higher gem-like compounds
- s-block metals – lists some alkali and earth alkali silicates (among other compounds)
- Iron – lists a few iron silicates
Phosphate minerals
- Especially interesting: Hydoxy- Fluor- & Clorapatite Ca5(PO4)3(F,Cl,OH) - (Mohs 5 defining mineral) - a biomineral [3]
- Lazulite (wikipedia) & Scorzalite (wikipedia) magnesium iron aluminium phosphates - (Mohs 5.5-6)
- Phosphophyllite (wikipedia) - zinc iron phosphate - rather soft (Mohs 3.5)
- Pb5(PO4)3Cl pyromorphite (wikipedia) - relatively hard for a lead mineral (Mohs 3.5)
- Y(PO4) Xenotime (wikipedia) - rare yttrium - high symmetry (tetragonal) - (Mohs 4.5)
- Al2(PO4)(OH)3 augelite [4] Mohs 4-4.5
- FePO4 heterosite Wikipedia:Heterosit(de) Mohs 4-4.5
- MnPO4 purpurite [5] Mohs 4-5 (unabundant manganese)
- (MgFe)2PO4F magnesium and iron wagnerite [6] Mohs (?)
- FeAl2(PO4)2 anhydous iron scorzalite [7] Mohs 6
- MgAl2(PO4)2 anhydous magnesium scorzalite Mohs 6
- Zn2Fe(PO4)2•4H2O phosphophyllite [8] Mohs 3.5 (soft)
Carbonate minerals
(wikipedia - minerals) (wikipedia - artificial)
- Calcite Mohs 3 (defining mineral) & Aragonite Mohs 3.5-4 - calcium
- Magnesite Mohs 3.5-4.5 - magnesium
- CaMg(CO3)2 Dolomite [9] – Mohs 3.5-4 – Trigonal Rhombohedral
- Siderite - iron
- Smithsonite - zinc
- Malachite & Azurite - copper
- Rhodochrosite - manganese (rare)
- ...
- Mg3Ca(CO3)4 Huntite [10] Mohs 1-2 (very soft!)
- PbCO3 Cerussite [11] Mohs 3-3.5 (soft)
Sulfate minerals
Sulfate minerals are generally rather soft with few exceptions.
One of the harder ones is brochantite (wikipedia) - (Mohs 3.5-4)
- CaSO4 anhydrite [12] (decomposes slowly to hydroxyde gypsum)
Borate minerals
- Mg3B7O13Cl Boracite (wikipedia) - (Mohs 7-7.5)
- Mn3B7O13Cl Chambersite (wikipedia) - (Mohs 7)
- Al6B5O15(F,OH)3 Jeremejevite (wikipedia) - (Mohs 6.5-7.5)
- Mg7(BO3)3(OH)4Cl Karlite (wikipedia) - (Mohs 5½)
- Ca2B5SiO9(OH)5 Howlite (wikipedia) - soft (Mohs 3.5)
- MnSn(BO3)2 Tusionite (wikipedia) - (Mohs 5-6) - tin
- CaZrAl9O15(BO3) Painite (wikipedia) - rare zirconium (Mohs 8)
- ...
Nitrate and Aluminates
All rather water soluble. See: (wikipedia - minerals) (wikipedia - artificial)
Aluminates: (wikipedia)
Salts of metal oxoacids
TODO ...
Related
External links
Wikipedia:
- Solubility chart: https://en.wikipedia.org/wiki/Solubility_chart
- Oxoacid
- Category:Oxoacids
