Product Overview
Hydrofluorosilicic Acid 23% ACS (CAS 16961-83-4), also sold as fluorosilicic acid, is a colorless, fuming aqueous acid with a sharp, pungent odor. It is the workhorse fluoride source for municipal water fluoridation and a precursor for fluorine chemistry, supplied here at ACS Grade for buyers who need a grade tier material rather than a bulk commodity cut. It is aggressively corrosive to metals and tissue — this is a product for trained operators with proper PPE and compatible transfer equipment, not casual use.
we distribute it in our Taylor, TX warehouse and ship it daily under full DOT hazmat protocol. Every container leaves sealed in UN-spec packaging with hazmat labeling and paperwork already done, whether you order a single quart for the lab or a 330 gallon tote for a treatment plant.
Why This Concentration
23% is the practical standard strength for fluorosilicic acid in service. It carries enough active fluoride for fluoridation dosing and synthesis work while remaining a pumpable, meterable liquid that standard chemical-feed equipment handles well. ACS Grade means the material is held to reagent-level purity — the right call when you are dosing potable water, running analytical work, or feeding a synthesis where trace impurities matter.
The trade-off at this strength is handling severity. The liquid fumes, and both the vapor and brief skin contact cause severe burns, so the concentration that makes your dosing efficient also demands closed transfer, ventilation, and disciplined PPE. If your process tolerates it, dilute at the point of use rather than storing dilutions long-term.
Chemical Profile
Fluorosilicic acid (formula H2SiF6, molecular weight 144.091, CAS 16961-83-4) presents as a colorless fuming liquid with a sour, penetrating pungent odor. The 23% w/w aqueous solution has a density of 1.19 at 20 °C — noticeably heavier than water, which matters when sizing day tanks and calibrating metering pumps by weight. It is corrosive to metals and tissue; fumes alone are enough to attack exposed steel fittings in a poorly ventilated storage area. It arrives as a ready-to-meter liquid, not a solid to dissolve.
Industrial Applications
Buyers put this acid to work in a handful of well-established roles:
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Water fluoridation — the dominant use. Treatment plants meter fluorosilicic acid into finished water as the fluoride source; the liquid feeds cleanly through standard chemical dosing skids.
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Fluorine chemical synthesis — serves as a precursor for producing fluorosilicate salts and other fluorine-bearing compounds.
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pH adjustment — used to trim pH downward in water and wastewater treatment trains where a fluoride contribution is acceptable or intended.
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Electroplating — functions in plating baths and surface-finishing lines where fluorosilicate chemistry improves deposit quality on metal coatings.
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Laboratory reagent — the ACS Grade purity makes this cut suitable for analytical and bench procedures that specify fluorosilicic acid.
Handling & Storage
This product carries the signal word Danger (per the product's GHS classification), with the following hazard statements: H302 Harmful if swallowed; H311 Toxic in contact with skin; H332 Harmful if inhaled; H314 Causes severe skin burns and eye damage; H335 May cause respiratory irritation; H402 Harmful to aquatic life (per the product's GHS classification).
Treat it accordingly. Wear acid-resistant gloves, splash goggles or a face shield, and body covering rated for corrosive acids; work with mechanical ventilation or respiratory protection where fumes can accumulate. Store cool and dry in HDPE or other compatible polyethylene containment, away from incompatible materials — and keep it away from glass and silicate-based materials, which fluorosilicic acid attacks. Keep containers closed; the liquid fumes and the vapors are corrosive to surrounding metalwork. Keep neutralizing agent and an eyewash/safety shower within reach of any transfer point. This handling guidance is reviewed by Andre Taki, DOT Hazmat Specialist.
Hazmat & Shipping
This product ships as a fully regulated corrosive. It moves under UN1778 (per 49 CFR 172.101), Hazard Class 8 (per 49 CFR 172.101), Packing Group II (per 49 CFR 172.101), with the proper shipping name Fluorosilicic acid (per 49 CFR 172.101). We pack every order in UN-specification packaging with correct marks, labels, and shipping papers before it leaves our dock — you receive a shipment that is compliant on arrival, with no hazmat paperwork left for you to fix.
Documentation
A Safety Data Sheet ships with every order and is available in English, Spanish, French, and Japanese. A lot-specific Certificate of Analysis is available for the material you receive, and a Technical Data Sheet is available on request — useful when your QC program requires traceability from receiving through dosing records.
Why Buy from Alliance Chemical
We are hazmat distribution operators. This acid is stocked, packed, and shipped daily from our Taylor, TX warehouse by a team that handles Class 8 corrosives every working day. Orders go out in DOT-compliant UN-spec packaging, from quart bottles for bench work to 55 gallon drums and 275–330 gallon totes for plant-scale feed systems. Shipping and handling guidance on this page is reviewed by Andre Taki, DOT Hazmat Specialist. If you run a treatment plant, a plating line, or a lab that needs grade tier fluorosilicic acid with clean paperwork, this is the straightforward way to buy it.
