Sodium Silicofluoride
An industrial grade fluoride salt, supplied as sodium hexafluorosilicate for process auxiliary duty, glass and enamel opacification and fluorine chemical manufacture.
What is Sodium Silicofluoride?
Sodium Silicofluoride is a white crystalline powder made up of sodium ions and the hexafluorosilicate anion, in which a central silicon atom is surrounded by six fluorines in an octahedron.
Locking the fluoride up in that anion is what gives the material its character. It is only sparingly soluble in water, so it behaves as a slow-release fluoride source that can be dosed and blended as a dry solid rather than handled as a concentrated soluble salt. That makes it the practical choice as a process auxiliary, as an opacifier and flux in opal glass and vitreous enamel, and as a feedstock for other fluorine chemicals.
At Chelora Dyes, SSF is supplied dried and screened with free acid held low, so it stays free flowing, doses consistently, and does not carry acidity into a batch where fluoride release must stay controlled.
- Appearance
- White crystalline powder
- Odour
- Odourless
- Solubility
- Sparingly in water
- Function
- Fluoride source
- Grade
- Industrial / technical
Sodium salt of the hexafluorosilicate anion
- Molecular formulaNa2SiF6
- Molecular weight188.06 g/mol
- IUPAC nameSodium hexafluorosilicate
- StructureIonic; octahedral SiF6 anion
- CAS number16893-85-9
Technical product information
Standard specification for Chelora Dyes' industrial grade Sodium Silicofluoride. Higher assay and alternative mesh grades are available on request.
| Chemical name | Sodium Silicofluoride |
|---|---|
| Synonyms | Sodium hexafluorosilicate, Sodium fluorosilicate, SSF |
| CAS number | 16893-85-9 |
| Molecular formula | Na2SiF6 |
| Molecular weight | 188.06 g/mol |
| Assay (dry basis) | ≥ 98.5% |
| Appearance | White crystalline powder |
| Thermal behaviour | Decomposes above approx. 300°C; does not melt |
| Free acid (as HF) | ≤ 0.2% |
| Moisture content | ≤ 0.5% |
| Water insoluble matter | ≤ 0.4% |
| Iron (as Fe) | ≤ 0.05% |
| Solubility | Sparingly soluble in water (approx. 0.65 g/100 mL at 20°C) |
| Transport classification | UN 2674, sodium fluorosilicate (verify against current documentation) |
| Packaging | 25 kg / 50 kg lined bags, 1000 kg jumbo bags |
| Shelf life | 24 months in sealed original packaging |
Applications of Sodium Silicofluoride
Process auxiliary
Used as a controlled fluoride source in dye and pigment plant auxiliary operations.
Opal glass and enamel
Acts as opacifier and flux in opal glass, vitreous enamel and glazing systems.
Ceramic frits
Blended dry into frit batches where fluoride modifies melt behaviour and opacity.
Acid-resistant cement
Used as a hardening and acid-resistance additive in specialist cement and concrete.
Fluorine chemicals
Raw material for sodium fluoride, aluminium fluoride and related fluorine compounds.
Water treatment
Supplied to municipal specifications where fluoridation is practised and permitted.
Why choose Chelora Dyes
Consistent purity
Assay controlled at ≥98.5% with free acid and moisture verified before dispatch.
Full documentation
COA, SDS, and transport classification supplied with every shipment.
Compliant logistics
Dangerous goods packing and paperwork handled to the applicable mode.
Technical support
Dosing, segregation, and compliance guidance from our chemistry team.
Storage and guidelines
- Store in sealed original bags in a cool, dry, well-ventilated store.
- Segregate strictly from all acids — contact liberates hydrogen fluoride.
- Keep away from heat; the salt decomposes rather than melts, releasing silicon tetrafluoride.
- Store away from foodstuffs, feed and drinking water systems.
- Keep bags off the floor and re-seal part-used bags promptly.
- Contain spillage as a dry solid; do not wash into drains.
Handling precautions
Sodium Silicofluoride is toxic if swallowed or inhaled. Fluoride poisoning can be serious and its effects are systemic, not just local.
Contact with acids liberates hydrogen fluoride, which causes deep, slow-healing burns and can be absorbed through skin with delayed systemic effects. Acid segregation is the critical control for this product.
Control dust rigorously at weighing, charging and bag emptying. Use chemically resistant gloves, chemical splash goggles, protective clothing and respiratory protection, with local exhaust ventilation at every dust-generating point.
Ensure operators and first-aiders know the specific first-aid response for fluoride and hydrogen fluoride exposure, and refer to the full Safety Data Sheet before any handling operation.
Frequently asked questions
What is Sodium Silicofluoride used for?
It is a solid, slow-release source of fluoride. In industry it is used as a process auxiliary and fluorinating salt, in opal glass and vitreous enamel where fluoride acts as an opacifier and flux, in ceramic frits, in acid-resistant cement and concrete hardening, and as a raw material for other fluorine chemicals.
Why is its low solubility useful?
It dissolves only sparingly in water, so it releases fluoride gradually rather than all at once. That makes it easier to dose and control than a freely soluble fluoride salt, and it allows the solid to be blended directly into batches and frits.
What happens if it contacts acid?
Contact with acids liberates hydrogen fluoride and silicon tetrafluoride, both of which are severely hazardous. This is the single most important incompatibility for this product and acids must be strictly segregated from it in storage and in process.
Is it stable on heating?
It decomposes rather than melts, giving off silicon tetrafluoride and leaving sodium fluoride behind. Keep it away from heat sources, and ensure any process that heats it is properly extracted and scrubbed.
What purity do you supply?
Standard industrial grade is supplied at a minimum assay of 98.5% on a dry basis, with free acid, moisture and water insoluble matter held within tight limits. Higher assay grades can be supplied to order.
What packaging sizes are available?
25 kg and 50 kg HDPE-lined bags, with bulk supply in 1000 kg jumbo bags.
How should it be stored, and for how long?
In sealed original bags in a cool, dry, well-ventilated store, strictly segregated from acids and away from heat. Shelf life is 24 months from manufacture when storage conditions are maintained.
Is it hazardous to handle?
Yes, seriously so. It is toxic if swallowed or inhaled, irritates skin, eyes and the respiratory tract, and releases hydrogen fluoride on contact with acid. Dust control and full personal protective equipment are essential, and the current Safety Data Sheet must be reviewed before any handling operation.
