Pyrosilicic acid

Pyrosilicic acid
Names
	IUPAC name Trihydroxysilyl trihydrogen orthosilicate
	Other names disilicic acid
Identifiers
3D model (JSmol)	Interactive image;
ChEBI	CHEBI:29292 ;
ChemSpider	55684 ;
Gmelin Reference	26937
PubChem CID	61804;
CompTox Dashboard (EPA)	DTXSID201014501 ;
	InChI InChI=1S/H6O7Si2/c1-8(2,3)7-9(4,5)6/h1-6H Key: KDJOAYSYCXTQGG-UHFFFAOYSA-N ;
	SMILES O[Si](O)(O)O[Si](O)(O)O;
Properties
Chemical formula	H6O7Si2
Molar mass	174.211 g·mol−1
Conjugate base	Pyrosilicate
	Except where otherwise noted, data are given for materials in their standard state (at 25 °C [77 °F], 100 kPa). (what is ?) Infobox references

Pyrosilicic acid is the chemical compound with formula (HO)
₃Si-O-Si(OH)
₃. It was synthesized, using non-aqueous solutions, in 2017.^[1] It may be present in sea water and other natural waters at very low concentration.^[2]^[3] Its low solubility in water is due to the preferential formation of its insoluble anhydride, silica, SiO₂.

H₆Si₂O₇ (aq) → 2SiO₂↓ + 3H₂O

Salts of pyrosilicic acid, such as sodium pyrosilicate are found in nature, in sorosilicates.

References

^ Igarashi, Masayasu; Matsumoto, Tomohiro; Yagahashi, Fujio; Yamashita, Hiroshi; Ohhara, Takashi; Hanashima, Takayasu; Nakao, Akiko; Moyosh, Taketo; Sato, Kazuhiko; Shimada, Shigeru (2017). "Non-aqueous selective synthesis of orthosilicic acid and its oligomers". Nature Communications. 8 (1): 140. doi:10.1038/s41467-017-00168-5. PMC 5529440. PMID 28747652.
^ Katsumi Goto (1956): "Effect of pH on Polymerization of Silicic Acid". Journal of Physical Chemistry, volume 60, issue 7, pages 1007–1008. doi:10.1021/j150541a046
^ M. F. Bechtold (1955): "Polymerization and Properties of Dilute Aqueous Silicic Acid from Cation Exchange". Journal of Physical Chemistry, volume 59, issue 6, pages 532–541. doi:10.1021/j150528a013

[synthesis-1] Igarashi, Masayasu; Matsumoto, Tomohiro; Yagahashi, Fujio; Yamashita, Hiroshi; Ohhara, Takashi; Hanashima, Takayasu; Nakao, Akiko; Moyosh, Taketo; Sato, Kazuhiko; Shimada, Shigeru (2017). "Non-aqueous selective synthesis of orthosilicic acid and its oligomers". Nature Communications. 8 (1): 140. doi:10.1038/s41467-017-00168-5. PMC 5529440. PMID 28747652.

[goto-2] Katsumi Goto (1956): "Effect of pH on Polymerization of Silicic Acid". Journal of Physical Chemistry, volume 60, issue 7, pages 1007–1008. doi:10.1021/j150541a046

[bech-3] M. F. Bechtold (1955): "Polymerization and Properties of Dilute Aqueous Silicic Acid from Cation Exchange". Journal of Physical Chemistry, volume 59, issue 6, pages 532–541. doi:10.1021/j150528a013

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