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FLUOROSILICIC ACID ICSC: 1233
Date of Peer Review: October 2004

Hexafluorosilicic acid
Dihydrogen hexafluorosilicate
Fluosilicic acid
Hydrosilicofluoric acid
CAS # 16961-83-4 F6H2Si / H2SiF6
RTECS # VV8225000 Molecular mass: 144.1
UN # 1778
EC # 009-011-00-5
TYPES OF HAZARD / EXPOSURE ACUTE HAZARDS / SYMPTOMS PREVENTION FIRST AID / FIRE FIGHTING
FIRE Not combustible. Gives off irritating or toxic fumes (or gases) in a fire.

In case of fire in the surroundings: use appropriate extinguishing media.
EXPLOSION


EXPOSURE
AVOID ALL CONTACT!
IN ALL CASES CONSULT A DOCTOR!
Inhalation Burning sensation. Cough. Laboured breathing. Shortness of breath. Symptoms may be delayed (see Notes).
Ventilation, local exhaust, or breathing protection.
Fresh air, rest. Half-upright position. Refer for medical attention.
Skin Redness. Pain. Skin burns.
Protective gloves. Protective clothing.
Remove contaminated clothes. Rinse skin with plenty of water or shower. Immediately refer for medical attention.
Eyes Redness. Pain. Severe deep burns.
Face shield or eye protection in combination with breathing protection.
First rinse with plenty of water for several minutes (remove contact lenses if easily possible), then take to a doctor.
Ingestion Burning sensation. Abdominal cramps. Vomiting. Shock or collapse.
Do not eat, drink, or smoke during work.
Rinse mouth. Do NOT induce vomiting. Give plenty of water to drink. Refer for medical attention.
SPILLAGE DISPOSAL PACKAGING & LABELLING
Personal protection: complete protective clothing including self-contained breathing apparatus. Collect leaking and spilled liquid in sealable iron containers as far as possible. Absorb remaining liquid in sand or inert absorbent and remove to safe place Do NOT let this chemical enter the environment.
Unbreakable packaging; put breakable packaging into closed unbreakable container. Do not transport with food and feedstuffs.
EU Classification
Symbol: C
R: 34
S: (1/2-)-26-27-45
Note: [B]
UN Classification
UN Hazard Class: 8
UN Pack Group: II
EMERGENCY RESPONSE STORAGE
Transport Emergency Card: TEC (R)-80S1778 and 80GC1-II+III
Separated from strong bases, food and feedstuffs. Well closed.
IPCS
International
Programme on
Chemical Safety
Prepared in the context of cooperation between the International Programme on Chemical Safety and the Commission of the European Communities IPCS, CEC 1999

SEE IMPORTANT INFORMATION ON BACK
FLUOROSILICIC ACID ICSC: 1233
IMPORTANT DATA
PHYSICAL STATE; APPEARANCE:
FUMING COLOURLESS LIQUID, WITH PUNGENT ODOUR.

CHEMICAL DANGERS:
The substance decomposes on heating producing toxic fumes including hydrogen fluoride. The solution in water is a strong acid, it reacts violently with bases and is corrosive. Reacts with water or steam to produce toxic and corrosive fumes. Attacks glass and stoneware. Attacks many metals forming flammable/explosive gas (hydrogen - see ICSC 0001). This substance (anhydrous form) dissociates almost instantly into silicon tetrafluoride and corrosive and toxic hydrogen fluoride.

OCCUPATIONAL EXPOSURE LIMITS:
TLV: (as F) 2.5 mg/m as TWA; A4 (not classifiable as a human carcinogen); BEI issued; (ACGIH 2004).
MAK not established.
ROUTES OF EXPOSURE:
The substance can be absorbed into the body by inhalation of its aerosol and by ingestion.

INHALATION RISK:
No indication can be given about the rate in which a harmful concentration in the air is reached on evaporation of this substance at 20C.

EFFECTS OF SHORT-TERM EXPOSURE:
The substance is corrosive to the eyes, the skin and the respiratory tract. Corrosive on ingestion. Inhalation of the vapour of this substance may cause lung oedema (see Notes). The effects may be delayed. Medical observation is indicated. See Notes.

EFFECTS OF LONG-TERM OR REPEATED EXPOSURE:
The substance may have effects on the bones and teeth, resulting in fluorosis.
PHYSICAL PROPERTIES
Decomposes below boiling point
Melting point: see Notes
Relative density (water = 1): see Notes
Solubility in water: miscible
Vapour pressure, kPa at 20C: see Notes
ENVIRONMENTAL DATA
This substance may be hazardous in the environment; special attention should be given to aquatic organisms.
NOTES
Marketed only as aqueous solution. Solidification point for 60-70% solution: solidifies at about 19C, forming a crystalline dihydrate. Melting point for 35% solution: <-30C. Relative density for a 61% solution is 1.46 and for 35% solution is 1.38. Vapour pressure for a 35% solution is about 3 kPa. The symptoms of lung oedema often do not become manifest until a few hours have passed and they are aggravated by physical effort. Rest and medical observation are therefore essential. Temperature of decomposition unknown in literature. Immediate administration of an appropriate inhalation therapy by a doctor or a person authorized by him/her, should be considered.
Card has been partly updated in April 2005. See sections Occupational Exposure Limits, EU classification,.
ADDITIONAL INFORMATION


LEGAL NOTICE Neither the CEC nor the IPCS nor any person acting on behalf of the CEC or the IPCS is responsible for the use which might be made of this information
IPCS, CEC 1999