Sodium pyrosilicate: Difference between revisions

Sodium pyrosilicate
Names
	Other names hexasodium diorthosilicate
Identifiers
CAS Number	15593-82-5 ;
3D model (JSmol)	Interactive image;
EC Number	239-671-1;
PubChem CID	61803;
UNII	VNJ6H8MB6Z ;
	InChI InChI=1S/6Na.O7Si2/c;;;;;;1-8(2,3)7-9(4,5)6/q6*+1;-6 Key: PMYUVOOOQDGQNW-UHFFFAOYSA-N;
	SMILES [Si](O[Si]([O-])([O-])[O-])([O-])([O-])[O-].[Na+].[Na+].[Na+].[Na+].[Na+].[Na+];
Properties
Chemical formula	Na6O7Si2
Molar mass	306.102 g·mol−1
	Except where otherwise noted, data are given for materials in their standard state (at 25 °C [77 °F], 100 kPa). (what is ?) Infobox references

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Latest revision as of 16:52, 8 November 2023

Sodium pyrosilicate is the chemical compound Na
₆Si
₂O
₇. It is one of the sodium silicates, specifically a pyrosilicate, formally a salt of the unstable pyrosilicic acid H
₆Si
₂O
₇.^[1]^[2]

Structure

The anhydrous solid has the triclinic crystal structure, with space group P1 (a = 5.8007(8) Å, b = 11.5811(15) Å, c = 23.157(3) Å, α = 89.709(10)°, β = 88.915(11)°, γ = 89.004(11)°, V = 1555.1(4) Å³, Z = 8, Dx = 2.615 g·cm⁻³, μ(Mo‐Kα) = 7.94 cm⁻¹). The Si
₂O⁶⁻
₇ anions are arranged in layers parallel to the (100) plane, with the sodium cations distributed in 24 distinct crystallographic positions, coordinated by 4 to 6 near oxygen atoms. Some of the 4-coordinated sodium atoms can be interpreted as parallel columns of edge-sharing NaO
₄ tetrahedra. The columnar arrangement forms tunnels that house the remaining sodium cations. Twinning at a microscopic scale simulates a much larger monoclinic C centered lattice (V′ = 6220 Å³, Z = 32).^[3]

References

^ Myron C Waddell (1932): "Process of purifying technical sodium pyrosilicate hydrates". US patent US1931364A.
^ J. F. Schairer and N. L. Bowen (1956): "The system Na
₂O—Al
₂O
₃—SiO
₂". American Journal of Science, volume 254, issue 3, pages 129-195 doi:10.2475/ajs.254.3.129
^ Volker Kahlenberg, Thomas Langreiter, and Erik Arroyabe (2010): "Na6Si2O7 – The Missing Structural Link among Alkali Pyrosilicates". Zeitschrift für anorganishe und allgemeine Chemie (Journal for Inorganic and General Chemistry), volume 636, issue 11, pages 1974-1979. doi:10.1002/zaac.201000120

[waddell-1] Myron C Waddell (1932): "Process of purifying technical sodium pyrosilicate hydrates". US patent US1931364A.

[sche-2] J. F. Schairer and N. L. Bowen (1956): "The system Na
₂O—Al
₂O
₃—SiO
₂". American Journal of Science, volume 254, issue 3, pages 129-195 doi:10.2475/ajs.254.3.129

[kahle-3] Volker Kahlenberg, Thomas Langreiter, and Erik Arroyabe (2010): "Na6Si2O7 – The Missing Structural Link among Alkali Pyrosilicates". Zeitschrift für anorganishe und allgemeine Chemie (Journal for Inorganic and General Chemistry), volume 636, issue 11, pages 1974-1979. doi:10.1002/zaac.201000120

[1]

[2]

[3]

@@ Line 39: / Line 39: @@
 ==Structure==
-The anhydrous solid has the [[triclinic]] crystal structure, with space group {{chem|P|1|-}} (a = 5.8007(8) [[angstrom|Å]], b = 11.5811(15) Å, c = 23.157(3) Å, α = 89.709(10)°, β = 88.915(11)°, γ = 89.004(11)°, V = 1555.1(4) Å<sup>3</sup>, Z = 8, Dx = 2.615 g·cm<sup>−3</sup>, μ(Mo‐Kα) = 7.94&nbsp;cm<sup>−1</sup>).  The {{chem|Si|2|O|7|6+}} anions are arranged in layers parallel to the (100) plane, with the sodium cations distributed in 24 distinct crystallographic positions, coordinated by 4 to 6 near oxygen atoms. Some of the 4-coordinated sodium atoms can be interpreted as parallel columns of edge-sharing {{chem|NaO|4}} tetrahedra.  The columnar arrangement forms tunnels that house the remaining sodium cations.  Twinning at a microscopic scale simulates a much larger monoclinic C centered lattice (V′ = 6220 Å<sup>3</sup>, Z = 32).<ref name=kahle>Volker Kahlenberg, Thomas Langreiter, and Erik Arroyabe (2010): "Na6Si2O7 – The Missing Structural Link among Alkali Pyrosilicates". ''Zeitschrift für anorganishe und allgemeine Chemie'' (''Journal for Inorganic and General Chemistry''), volume  636, issue 11, pages 1974-1979. {{doi|10.1002/zaac.201000120}}</ref>
+The anhydrous solid has the [[triclinic]] crystal structure, with space group P{{overline|1}} (a = 5.8007(8) [[angstrom|Å]], b = 11.5811(15) Å, c = 23.157(3) Å, α = 89.709(10)°, β = 88.915(11)°, γ = 89.004(11)°, V = 1555.1(4) Å<sup>3</sup>, Z = 8, Dx = 2.615 g·cm<sup>−3</sup>, μ(Mo‐Kα) = 7.94&nbsp;cm<sup>−1</sup>).  The {{chem|Si|2|O|7|6-}} anions are arranged in layers parallel to the (100) plane, with the sodium cations distributed in 24 distinct crystallographic positions, coordinated by 4 to 6 near oxygen atoms. Some of the 4-coordinated sodium atoms can be interpreted as parallel columns of edge-sharing {{chem|NaO|4}} tetrahedra.  The columnar arrangement forms tunnels that house the remaining sodium cations.  Twinning at a microscopic scale simulates a much larger monoclinic C centered lattice (V′ = 6220 Å<sup>3</sup>, Z = 32).<ref name=kahle>Volker Kahlenberg, Thomas Langreiter, and Erik Arroyabe (2010): "Na6Si2O7 – The Missing Structural Link among Alkali Pyrosilicates". ''Zeitschrift für anorganishe und allgemeine Chemie'' (''Journal for Inorganic and General Chemistry''), volume  636, issue 11, pages 1974-1979. {{doi|10.1002/zaac.201000120}}</ref>
 ==See also==