Selenium hexafluoride

  • Selenium(VI) fluoride
Formula
SeF6
Structure
Description
Colorless gas.
Uses
Gaseous electric insulator.

Registry Numbers and Inventories.
CAS
7783-79-1
RTECS
VS9450000
RTECS class
Other
UN (DOT)
2194
Merck
12,8575
Beilstein/Gmelin
68800 (G)
RCRA
D010
Swiss Giftliste 1
G-2845

Properties.
Formula
F6Se
Formula mass
192.95
Melting point, °C
-33.91
Boiling point, °C
-35
Vapor pressure, mmHg
93.6 (-78.5 C)
Vapor density (air=1)
6.7
Critical temperature
72
Density
2.108 g/cm3 (-10 C)
Solubility in water
Insoluble
Thermal expansion
0.0026/K
Heat of fusion
4.60 kJ/mol

Hazards and Protection.
Storage
Keep in a cool, dry, dark location in a tightly sealed container or cylinder. Keep away from incompatible materials, ignition sources and untrained individuals. Secure and label area. Protect containers/cylinders from physical damage.
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 chemical protective clothing.
Respirators
Wear positive pressure self-contained breathing apparatus (SCBA).
Small spills/leaks
Keep sparks, flames, and other sources of ignition away. Keep material out of water sources and sewers. Attempt to stop leak if without undue personnel hazard. Use water spray to knock-down vapors.
Stability
No data.
Incompatibilities
Reacts with ammonia gas at 200 C to give selenium, nitrogen, and hydrogen fluoride water.
Decomposition
Decomposes when dissolved in water. When heated to decomposition, emits very toxic fumes of hydrogen fluoride and selenium.

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. Use foam, dry chemical, or carbon dioxide. Do not apply water to point of leak in tank car or container.
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.
Combustion products
When heated to high temperatures it may decompose to emit toxic fluoride and selenium fumes.
Health
3

Health.
Exposure limit(s)
TLV (as Se): 0.05 ppm; mg/m3 (ACGIH 1990-1991). MAK: 0.025 ppm; 0.2 mg/m3; (199?). OSHA PEL: TWA 0.05 ppm (0.4 mg/m3) NIOSH REL: TWA 0.05 ppm NIOSH IDLH: 2 ppm
Poison_Class
1
Exposure effects
Hyperactive reflexes, painful muscle spasms, weakness and tetanic contractures may be noted due to fluoride induced hypocalcemia. Prenatal fluoride supplementation (2.2 mg NaF or 1 mg fluoride daily) during the last two trimesters of pregnancy has been reported to be safe.
   Ingestion
Epigastric pain, nausea, dysphagia, salivation, hematemesis, and diarrhea may be noted. These effects may be delayed for several hours following exposure. Gi symptoms are noted when 3 to 5 mg/kg of fluoride are ingested.
   Inhalation
Respirations are first stimulated then depressed. Death is usually from respiratory paralysis. Following inhalation, coughing and choking may be noted.
   Skin
Urticaria and pruritus have been reported following exposure to fluoride.
   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 contaminated clothing and wash exposed area thoroughly with soap and water. A physician should examine the area if irritation or pain persists.
   Eyes
Irrigate exposed eyes with copious amounts of tepid water for at least 15 minutes. If irritation, pain, swelling, lacrimation, or photophobia persist, the patient should be seen in a health care facility.

Transport.
UN number
2194
Response guide
Hazard class
2.3
PRTC
T
Std. Transport #
4920106