Sodium fluorosilicate

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Sodium fluorosilicate
Unit cell of the compound
Unit cell of sodium hexafluoridosilicate
Preferred IUPAC name
Sodium fluorosilicate
Systematic IUPAC name
Sodium hexafluoridosilicate(2–) [1]
Other names
Disodium hexafluorosilicate/sodium fluosilicate/sodium silicofluoride
3D model (JSmol)
ECHA InfoCard 100.037.198 Edit this at Wikidata
EC Number
  • 240-934-8
RTECS number
  • VV8410000
UN number 2674
Molar mass 188 g/mol
Appearance white granular powder
Odor odorless
Density 2.7 g/cm3
0.64 g/100 mL (20 °C)
1.27 g/100 mL (50 °C)
2.45 g/100 mL (100 °C)
Solubility insoluble in alcohol
a = 8.859, c = 5.038
NFPA 704 (fire diamond)
Flammability code 0: Will not burn. E.g. waterHealth code 2: Intense or continued but not chronic exposure could cause temporary incapacitation or possible residual injury. E.g. chloroformReactivity code 0: Normally stable, even under fire exposure conditions, and is not reactive with water. E.g. liquid nitrogenSpecial hazards (white): no codeNFPA 704 four-colored diamond
Lethal dose or concentration (LD, LC):
70 mg/kg (mouse, oral)
125 mg/kg (rabbit, oral)[3]
Related compounds
Other cations
Ammonium hexafluorosilicate

Fluorosilicic acid

Except where otherwise noted, data are given for materials in their standard state (at 25 °C [77 °F], 100 kPa).
Infobox references

Sodium fluorosilicate is a compound with the chemical formula Na2[SiF6].

Natural occurrence[edit]

Sodium hexafluorosilicate occurs naturally as the rare mineral malladrite found within some volcanic fumaroles.[4]


Sodium fluorosilicate is made by neutralizing fluorosilicic acid with sodium chloride or sodium sulfate.

H2[SiF6] + 2 NaCl → Na2[SiF6] + 2 HCl

Possible application[edit]

It is used in some countries as additives for water fluoridation, opal glass raw material, ore refining, or other fluoride chemical (like sodium fluoride, magnesium silicofluoride, cryolite, aluminum fluoride) production.[5]

See also[edit]


  1. ^ "Parent Hydride Names and Substitutive Nomenclature". Nomenclature of Inorganic Chemistry, IUPAC Recommendations 2005 (PDF). RSC Publishing. 2005. pp. 114–135.
  2. ^ Allan Zalkin, J. D. Forrester, David H. Templeton (1964). "The Crystal Structure of Sodium Fluorosilicate". Acta Crystallographica. 17 (11): 1408–1412. doi:10.1107/S0365110X64003516.CS1 maint: multiple names: authors list (link)
  3. ^ "Fluorides (as F)". Immediately Dangerous to Life and Health Concentrations (IDLH). National Institute for Occupational Safety and Health (NIOSH).
  4. ^
  5. ^ "Archived copy". Archived from the original on 2009-03-26. Retrieved 2009-08-10.CS1 maint: archived copy as title (link)