Selenium trioxide

  • Selenic anhydride
Formula
SeO3
Structure
Description
White Solid.

Registry Numbers and Inventories.
CAS
13768-86-0
EC (EINECS/ELINCS)
237-385-1
UN (DOT)
2928
Beilstein/Gmelin
100832 (G)

Properties.
Formula
O3Se
Formula mass
126.96
Melting point, °C
117.85 - 118.85
Decomposition point, °C
180
Density
3.6 g/cm3 (20 C)
Solubility in water
Very soluble, reacts

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 protective gloves, clothing and goggles.
Respirators
Wear positive pressure self-contained breathing apparatus (SCBA).
Small spills/leaks
Neutralizing Agents for Acids and Caustics: Flush with water, rinse with dilute solution of sodium bicarbonate or soda ash.
Stability
No data.
Incompatibilities
Can react with reducing agents to generate heat and products that may be gaseous (causing pressurization of closed containers) Can react violently with active metals, cyanides, esters, and thiocyanates.

Fire.
Fire fighting
Extinguish using agent most appropriate for surrounding fire.
Fire potential
Non-combustible, substance itself does not burn but may decompose upon heating to produce corrosive and/or toxic fumes.
Hazards
Contact with metals may evolve flammable hydrogen gas.
Combustion products
Fire may produce irritating, corrosive and/or toxic gases.

Health.
Exposure limit(s)
TLV (as Se): ppm; 0.02 mg/m3 (ACGIH 1990-1991). PDK (as Se): 0.1 mg/m3 (USSR 1977).
Exposure effects
   Ingestion
See Inhalation.
   Inhalation
TOXIC; inhalation, ingestion, or skin contact with material may cause severe injury or death. Effects of contact or inhalation may be delayed.
   Skin
Contact with molten substance may cause severe burns to skin and eyes. See Inhalation.
   Eyes
See Inhalation.

First aid
 
   Ingestion
Induce vomiting; follow with gastric lavage and saline cathartics.
   Inhalation
Remove victim to fresh air; give oxygen if necessary.
   Skin
Remove and isolate contaminated clothing and shoes. Immediately flush with running water for at least 20 minutes. For minor skin contact, avoid spreading material on unaffected skin.
   Eyes
Flush immediately and thoroughly with water.

Transport.
UN number
2928
Response guide
Hazard class
6.1
Packing Group
I; II
 
USCG CHRIS Code
STO