FLUOROSILICIC ACID

A colorless fuming liquid with a penetrating pungent odor. Corrosive to metals and tissue. Both the fumes and very short contact with the liquid can cause severe and painful burns. Used in water fluoridation, in hardening cement and ceramics, as a wood preservative.

• Known Catalytic Activity
• Water-Reactive

Fumes in air. Soluble in water with release of heat and corrosive fumes.

Special Hazards of Combustion Products: Irritating fumes of hydrogen fluoride may form in fire. (USCG, 1999)

Inhalation of vapor produces severe corrosive effect on mucous membrane. Ingestion causes severe burns of mouth and stomach. Contact with liquid or vapor causes severe burns of eyes and skin. (USCG, 1999)

FLUOROSILICIC ACID can react with strong acids (such as sulfuric acid) to release fumes of toxic hydrogen fluoride. Attacks glass and materials containing silica. Reacts exothermically with chemical bases (examples: amines, amides, inorganic hydroxides). Reacts with active metals, including iron and aluminum to dissolve the metal and liberate hydrogen and/or toxic gases. Can initiate polymerization in certain alkenes. Reacts with cyanide salts and compounds to release gaseous hydrogen cyanide. Flammable and/or toxic gases are also often generated by reactions with dithiocarbamates, isocyanates, mercaptans, nitrides, nitriles, sulfides, and weak or strong reducing agents. Additional gas-generating reactions may occur with sulfites, nitrites, thiosulfates (to give H2S and SO3), dithionites (SO2), and carbonates. Can catalyze (increase the rate of) chemical reactions. Decomposes when heated to the boiling point to produce very toxic and corrosive hydrogen fluoride gas.

• Acids, Strong Non-oxidizing
• Fluoride Salts, Soluble

Use caution: Liquids with this reactive group classification have been known to react with the absorbents listed below.

• Mineral-Based & Clay-Based Absorbents
• Sand
• Dirt/Earth

Excerpt from 154 [Substances - Toxic and/or Corrosive (Non-Combustible)]:

IMMEDIATE PRECAUTIONARY MEASURE: Isolate spill or leak area in all directions for at least 50 meters (150 feet) for liquids and at least 25 meters (75 feet) for solids.

SPILL: Increase the immediate precautionary measure distance, in the downwind direction, as necessary.

FIRE: If tank, rail car or tank truck is involved in a fire, ISOLATE for 800 meters (1/2 mile) in all directions; also, consider initial evacuation for 800 meters (1/2 mile) in all directions. (ERG, 2020)

Excerpt from 154 [Substances - Toxic and/or Corrosive (Non-Combustible)]:

SMALL FIRE: Dry chemical, CO2 or water spray.

LARGE FIRE: Dry chemical, CO2, alcohol-resistant foam or water spray. If it can be done safely, move undamaged containers away from the area around the fire. Dike runoff from fire control for later disposal.

FIRE INVOLVING TANKS OR CAR/TRAILER LOADS: Fight fire from maximum distance or use unmanned master stream devices or monitor nozzles. Do not get water inside containers. Cool containers with flooding quantities of water until well after fire is out. Withdraw immediately in case of rising sound from venting safety devices or discoloration of tank. ALWAYS stay away from tanks engulfed in fire. (ERG, 2020)

Excerpt from 154 [Substances - Toxic and/or Corrosive (Non-Combustible)]:

ELIMINATE all ignition sources (no smoking, flares, sparks or flames) from immediate area. Do not touch damaged containers or spilled material unless wearing appropriate protective clothing. Stop leak if you can do it without risk. Prevent entry into waterways, sewers, basements or confined areas. Absorb or cover with dry earth, sand or other non-combustible material and transfer to containers. DO NOT GET WATER INSIDE CONTAINERS. (ERG, 2020)

Rubber gloves; safety glasses; protective clothing (USCG, 1999)

Normalized Breakthrough Times (in Minutes)

Chemical	CAS Number	State	QS	QC	SL	C3	TF	TP	RC	TK	RF
Fluorosilicic acid (33-35%)	16961-83-4	Liquid			>480	>480	>480	>480	>480		>480

Special Warning from DuPont: Tychem® and Tyvek® fabrics should not be used around heat, flames, sparks or in potentially flammable or explosive environments. Only...

(DuPont, 2023)

INHALATION: remove victim to fresh air; get medical attention.

INGESTION: give large amounts of water; do NOT induce vomiting.

EYES: immediately wash with water for 15 min.; call a physician.

SKIN: wash affected parts with water; treat as for hydrogen fluoride burn with iced benzalkonium chloride soaks. (USCG, 1999)

• DIHYDROGEN HEXAFLUOROSILICATE
• DIHYDROGEN HEXAFLUOROSILICATE(2-)
• FLUOROSILIC ACID
• FLUOROSILICIC ACID
• FLUOROSILICIC ACID (H2SIF6)
• FLUOSILICIC ACID
• HEXAFLUOROSILICIC ACID
• HEXAFLUOSILICIC ACID
• HYDROFLUOROSILICIC ACID
• HYDROFLUOSILIC ACID
• HYDROFLUOSILICIC ACID
• HYDROGEN HEXAFLUOROSILICATE
• HYDROGEN HEXAFLUOROSILICATE (H2SIF6)
• SAND ACID
• SILICOFLUORIC ACID
• SILICON HEXAFLUORIDE DIHYDRIDE