Aluminium silicate

Aluminium silicate

Identifiers
CAS Number	12141-46-7
ChemSpider	8488719
Jmol interactive 3D	Image
PubChem	10313254
InChI InChI=1S/2Al.O3Si.2O/c;;1-4(2)3;;/q2*+1;-2;; Key: PZZYQPZGQPZBDN-UHFFFAOYSA-N
SMILES O=[Al]O[Si](=O)O[Al]=O
Properties
Chemical formula	Al 2SiO 5
Molar mass	162.0456 g mol^−1
Except where otherwise noted, data are given for materials in their standard state (at 25 °C [77 °F], 100 kPa).
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Infobox references

Aluminium silicate (or aluminum silicate) is a name commonly applied to chemical compounds which are derived from aluminium oxide, Al₂O₃ and silicon dioxide, SiO₂ which may be anhydrous or hydrated, naturally occurring as minerals or synthetic. Their chemical formulae are often expressed as xAl₂O₃.ySiO₂.zH₂O These include the compounds:-

• Al₂SiO₅, (Al₂O₃.SiO₂), which occurs naturally as the minerals andalusite, kyanite and sillimanite which have different crystal structures.
• Al₂Si₂O₅(OH)₄, (Al₂O₃·2SiO₂·2H₂O), which occurs naturally as the mineral kaolinite and is also called aluminium silicate dihydrate.^[1] It is a fine white powder and is used as a filler in paper and rubber and also used in paints.^[1]
• Al₂Si₂O₇, (Al₂O₃.2SiO₂), called metakaolinite, formed from kaolin by heating at 450 °C (842 °F).^[1]
• Al₆SiO₁₃, (3Al₂O₃.2SiO₂), the mineral mullite, the only thermodynamically stable intermediate phase in the Al₂O₃-SiO₂ system at atmospheric pressure.^[2] This also called '3:2 mullite' to distinguish it from 2Al₂O₃.SiO₂, Al₄SiO₈ '2:1 mullite'.
• 2Al₂O₃.SiO₂, Al₄SiO₈ '2:1 mullite'.^[2]

Aluminium silicate composite materials, fibres

Aluminium silicate is a type of fibrous material made of aluminium oxide and silicon dioxide, (such materials are also called aluminosilicate fibres). These are glassy solid solutions rather than chemical compounds. The compositions are often described in terms of % weight of alumina, Al₂O₃ and silica, SiO₂. Temperature resistance increases as the % alumina increases. These fibrous materials can be encountered as loose wool, blanket, felt, paper or boards.^[3]

See also

• Aluminosilicate

References

1. Handbook of Inorganic Compounds, Dale L. Perry, Taylor & Francis, 2011, ISBN 978-1-4398-1461-1
2. Ceramic and Glass Materials: Structure, Properties and Processing, James F. Shackelford, R. H. Doremus, Springer, 2008, ISBN 978-0-387-73361-6
3. Concise Encyclopedia of Composite Materials, ed. Anthony Kelly, MIT Press, 1989, ISBN 0-262-11145-4

External links

• Aluminum silicates at the University of Waterloo, Canada