sodium pyrosilicate

{{Chembox

| Verifiedfields = changed

| Watchedfields = changed

| verifiedrevid =

| IUPACName =

| OtherNames = hexasodium diorthosilicate

| ImageFile =

| ImageSize =

| ImageName =

|Section1={{Chembox Identifiers

| InChI1 = 1S/6Na.O7Si2/c;;;;;;1-8(2,3)7-9(4,5)6/q6*+1;-6

| InChIKey1 = PMYUVOOOQDGQNW-UHFFFAOYSA-N

| CASNo_Ref = {{cascite|changed|CAS}}

| CASNo = 15593-82-5

| UNII_Ref = {{fdacite|changed|FDA}}

| UNII = VNJ6H8MB6Z

| PubChem = 61803

| ChemSpiderID =

| ChemSpiderID_Ref = {{chemspidercite|correct|chemspider}}

| EINECS = 239-671-1

| UNNumber =

| ChEBI_Ref = {{ebicite|correct|EBI}}

| ChEBI =

| StdInChI_Ref = {{stdinchicite|correct|chemspider}}

| StdInChI =

| StdInChIKey_Ref = {{stdinchicite|correct|chemspider}}

| StdInChIKey =

| SMILES = [Si](O[Si]([O-])([O-])[O-])([O-])([O-])[O-].[Na+].[Na+].[Na+].[Na+].[Na+].[Na+]

| Gmelin =

}}

|Section2={{Chembox Properties

| MeltingPtC =

| Na=6 | O=7 | Si=2

}}

|Section3=

}}

Sodium pyrosilicate is the chemical compound {{chem|Na|6|Si|2|O|7}}. It is one of the sodium silicates, specifically a pyrosilicate, formally a salt of the unstable pyrosilicic acid {{chem|H|6|Si|2|O|7}}.Myron C Waddell (1932): "Process of purifying technical sodium pyrosilicate hydrates". US patent US1931364A.J. F. Schairer and N. L. Bowen (1956): "The system {{chem|Na|2|O}}—{{chem|Al|2|O|3}}—{{chem|SiO|2}}". American Journal of Science, volume 254, issue 3, pages 129-195 {{doi|10.2475/ajs.254.3.129}}

Structure

The anhydrous solid has the triclinic crystal structure, with space group P{{overline|1}} (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 {{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 Å³, Z = 32).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}}

References

Category:Sodium compounds

sodium pyrosilicate

Structure

See also

References