 Unit cell of sodium hexafluoridosilicate | |
| Names | |
|---|---|
| Preferred IUPAC name Sodium fluorosilicate | |
| Systematic IUPAC name Sodium hexafluoridosilicate(2–)[1] | |
| Other names Disodium hexafluorosilicate/sodium fluosilicate/sodium silicofluoride | |
| Identifiers | |
3D model (JSmol) | |
| ChemSpider |
|
| ECHA InfoCard | 100.037.198 |
| EC Number |
|
| RTECS number |
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| UNII | |
| UN number | 2674 |
| |
| |
| Properties | |
| Na2[SiF6] | |
| 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 |
Refractive index (nD) | 1.312 |
| Structure[2] | |
| trigonal | |
| P321 | |
a = 8.859,c = 5.038 | |
Formula units (Z) | 4 |
| Hazards | |
| NFPA 704 (fire diamond) | |
| Lethal dose or concentration (LD, LC): | |
LDLo (lowest published) | 70 mg/kg (mouse, oral) 125 mg/kg (rabbit, oral)[3] |
| Related compounds | |
Othercations | Ammonium hexafluorosilicate |
Except where otherwise noted, data are given for materials in theirstandard state (at 25 °C [77 °F], 100 kPa). | |
Sodium fluorosilicate is acompound with the chemical formula Na2[SiF6]. Unlike other sodium salts, it has a low solubility in water.
Sodium hexafluorosilicate occurs naturally as the rare mineral malladrite found within some volcanic fumaroles.[4]
Sodium fluorosilicate is made byneutralizingfluorosilicic acid withsodium chloride orsodium sulfate.
Sodium fluorosilicate is used in some countries as additives forwater fluoridation, opal glass raw material, ore refining, or other fluoride chemical (like sodium fluoride, magnesium silicofluoride, cryolite, aluminum fluoride) production.[5]
It is used for extraction ofberyllium fromberyl, by roasting the mineral with it at 700-750 °C, leaching the soluble fluoride with water, and then precipitating it asBe(OH)2 at about pH 13.[6]
It also is an ingredient in some ceramic cements.
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