Silicon tetrafluoride

  • Silicon fluoride
  • Tetrafluorosilane
  • Perfluorosilane
Formula
SiF4
Structure
Description
Colorless gas. Very pungent odor similar to that of hydrogen chloride.
Uses
Manufacture of fluosilicic acid, to seal water out of oil wells during drillings, intermediate in manufacture of pure silicon.

Registry Numbers and Inventories.
CAS
7783-61-1
EC (EINECS/ELINCS)
232-015-5
RTECS
VW2327000
RTECS class
Other
UN (DOT)
1859
Merck
12,8645
Beilstein/Gmelin
1949 (G)
Canada DSL/NDSL
DSL
US TSCA
Listed
Austrailia AICS
Listed
New Zealand
Listed
Japan ENCS (MITI)
Listed
Korea ECL
Listed

Properties.
Formula
F4Si
Formula mass
104.07
Melting point, °C
-77
Boiling point, °C
-86
Vapor pressure, mmHg
42 (-121.5 C)
Vapor density (air=1)
3.57
Critical temperature
-1.5
Critical pressure
5
Density
0.00469 g/cm3
Solubility in water
Decomposes
Thermal expansion
0.00375/K
Heat of fusion
7.07 kJ/mol

Hazards and Protection.
Storage
Preserve in tightly capped container.
Handling
All chemicals should be considered hazardous. Avoid direct physical contact. Use appropriate, approved safety equipment. Untrained individuals should not handle this chemical or its container. Handling should occur in a chemical fume hood.
Protection
Wear appropriate protective gloves, clothing and goggles.
Respirators
Wear positive pressure self-contained breathing apparatus.
Small spills/leaks
Keep material out of water sources and sewers. Attempt to stop leak if without undue personnel hazard. Use water spray to knock-down vapors. Neutralize spilled material with crushed limestone, soda ash, or lime. Do not use water on material itself.
Stability
Fumes strongly in air.
Incompatibilities
Reacts violently with alcohols to form HF Attacks many metals in the presence of moisture Reacts violently to explosively with lithium nitride Mixtures with sodium are shock-sensitive explosives.

Fire.
Fire fighting
Extinguish fire using agent suitable for type of surrounding fire. (Material itself does not burn or burns with difficulty.) Cool all affected containers with flooding quantities of water. Apply water from as far a distance as possible. Do not use water on material itself. Use water spray to knock-down vapors.
Fire potential
May burn but does not ignite readily.
Hazards
Vapors from liquefied gas are initially heavier than air and spread along ground. Some of these materials may react violently with water. Containers may explode when heated. Ruptured cylinders may rocket.
Health
3
 
Flammability
0
 
 
Reactivity
2
 
 
Special
W

Health.
Exposure limit(s)
TLV (as F (Fluorides)): ppm; 2.5 mg/m3 (ACGIH 1996).
Exposure effects
The toxological properties of this substance have not been fully investigated.
   Inhalation
Dyspnea, bronchospasm (with abnormal pfts and hypoxia), chemical pneumonitis, pulmonary edema (can be hemorrhagic), tracheobronchitis, upper airway obstruction, chemical burns (larynx, trachea, bronchi) and ards may occur following inhalation.
   Skin
Contact with gas or liquefied gas may cause burns, severe injury and/or frostbite.
   Eyes
See Skin.

First aid
 
   Ingestion
Seek medical assistance.
   Inhalation
Move victim to fresh air. Apply artificial respiration if victim is not breathing. Do not use mouth-to-mouth method if victim ingested or inhaled the substance; induce artificial respiration with the aid of a pocket mask equipped with a one-way valve or other proper respiratory medical device. Administer oxygen if breathing is difficult. Effects may be delayed.
   Skin
Remove all exposed clothing and jewelry taking necessary precautions to prevent secondary exposure to health care providers. Irrigate exposed areas promptly with copious amounts of water for at least 30 minutes. Wash the skin, including hair and nails, vigorously; do repeated soap washings. Discard contaminated clothing.
   Eyes
In case of contact with liquefied gas, thaw frosted parts with lukewarm water Immediately flush skin with running water for at least 20 minutes.

Transport.
UN number
1859
Response guide
Hazard class
2.3
PRTC
T
Std. Transport #
4920357