Sodium metasilicate

Sodium metasilicate
Structural formula of polymeric sodium silicate
Structural formula of polymeric sodium silicate
Ball and stick model of polymeric sodium silicate
Ball and stick model of polymeric sodium silicate
Sample of sodium silicate in a vial
Sample of sodium silicate in a vial
Names
IUPAC name
Sodium metasilicate
Identifiers
3D model (JSmol)
Abbreviations E550
ChEBI
ChemSpider
ECHA InfoCard 100.027.193 Edit this at Wikidata
EC Number
  • 600-279-4229-912-9
MeSH Sodium+metasilicate
RTECS number
  • VV9275000
UNII
UN number 1759 3253
  • InChI=1S/2Na.O3Si/c;;1-4(2)3/q2*+1;-2 checkY
    Key: NTHWMYGWWRZVTN-UHFFFAOYSA-N checkY
  • InChI=1/2Na.O3Si/c;;1-4(2)3/q2*+1;-2
    Key: NTHWMYGWWRZVTN-UHFFFAOYAB
  • [Na+].[Na+].[O-][Si]([O-])=O
Properties
Na2SiO3
Molar mass 122.062 g·mol−1
Appearance White crystals
Density 2.61 g/cm3
Melting point 1,088 °C (1,990 °F; 1,361 K)
22.2 g/100 ml (25 °C)
160.6 g/100 ml (80 °C)
Solubility insoluble in alcohol
1.52
Thermochemistry
111.8 J/(K·mol)
113.71 J/(K·mol)
−1561.43 kJ/mol
−1427 kJ/mol
Hazards
GHS labelling:
GHS05: CorrosiveGHS07: Exclamation mark
Danger
H302, H314, H315, H319, H335
P260, P264, P270, P271, P280, P301+P312, P301+P330+P331, P302+P352, P303+P361+P353, P304+P340, P305+P351+P338, P310, P312, P321, P330, P332+P313, P337+P313, P362, P363, P403+P233, P405, P501
NFPA 704 (fire diamond)
NFPA 704 four-colored diamondHealth 2: Intense or continued but not chronic exposure could cause temporary incapacitation or possible residual injury. E.g. chloroformFlammability 0: Will not burn. E.g. waterInstability 0: Normally stable, even under fire exposure conditions, and is not reactive with water. E.g. liquid nitrogenSpecial hazards (white): no code
2
0
0
Lethal dose or concentration (LD, LC):
1153 mg/kg (rat, oral)
Safety data sheet (SDS) Avantor Performance Materials
Related compounds
Other anions
Other cations
Except where otherwise noted, data are given for materials in their standard state (at 25 °C [77 °F], 100 kPa).
checkY verify (what is checkYX markN ?)

Sodium metasilicate is the chemical substance with formula Na
2SiO
3, which is the main component of commercial sodium silicate solutions. It is an ionic compound consisting of sodium cations Na+
 and the polymeric metasilicate anions [–SiO2−
3–]n. It is a colorless crystalline hygroscopic and deliquescent solid, soluble in water (giving an alkaline solution) but not in alcohols.

Structure

In the anhydrous solid, the metasilicate anion is actually polymeric, consisting of corner-shared {SiO4} tetrahedra, and not a discrete SiO32− ion.

In addition to the anhydrous form, there are hydrates with the formula Na2SiO3·nH2O (where n = 5, 6, 8, 9), which contain the discrete, approximately tetrahedral anion SiO2(OH)22− with water of hydration. For example, the commercially available sodium silicate pentahydrate Na2SiO3·5H2O is formulated as Na2SiO2(OH)2·4H2O, and the nonahydrate Na2SiO3·9H2O is formulated as Na2SiO2(OH)2·8H2O.

Preparation

The anhydrous compound can be prepared by fusing silicon dioxide SiO
2 (silica, quartz) with sodium oxide Na
2O in 1:1 molar ratio.

Uses

Sodium metasilicate reacts with acids to produce silica gel.

References

  1. ↑ Chemical Book: "Sodium metasilicate". Accessed on 2018-05-13.
  2. ↑ Greenwood, Norman N.; Earnshaw, Alan (1997). Chemistry of the Elements (2nd ed.). Butterworth-Heinemann. doi:10.1016/C2009-0-30414-6. ISBN 978-0-08-037941-8.
  3. ↑ Wells A.F. (1984) Structural Inorganic Chemistry 5th edition Oxford Science Publications ISBN 0-19-855370-6
  4. ↑ J. F. Schairer and N. L. Bowen (1956): "The system Na
    2    O    —Al
    2    O
    3    —SiO
    2    ". American Journal of Science, volume 254, issue 3, pages 129-195 doi:10.2475/ajs.254.3.129
  5. ↑ "Uses of Sodium Metasilicate". 24 April 2017.