Selenious acid

  • Selenous acid
  • Monohydrated selenium dioxide
Formula
H2SeO3
Structure
Description
Colorless solid, transparent, colorless crystals.
Uses
As reagent for alkaloids, as oxidizing agent.

Registry Numbers and Inventories.
CAS
7783-00-8
EC (EINECS/ELINCS)
231-974-7
R 23/25 33 50/53
S 20/21 28 45 60 61
RTECS
VS7175000
RTECS class
Agricultural Chemical and Pesticide; Mutagen
UN (DOT)
2811
Merck
12,8571
Beilstein/Gmelin
25856 (G)
RCRA
U204
Canada DSL/NDSL
DSL
US TSCA
Listed
Austrailia AICS
Listed
New Zealand
Listed
Japan ENCS (MITI)
Listed
Korea ECL
Listed

Properties.
Formula
H2O3Se
Formula mass
128.97
Melting point, °C
70
Boiling point, °C
315
Vapor pressure, mmHg
2
Density
1.998 g/cm3
Solubility in water
1670 g/L

Hazards and Protection.
Storage
Store in a cool, dry place. Store in a tightly closed container. Poison room locked.
Handling
Wash thoroughly after handling. Wash hands before eating. Remove contaminated clothing and wash before reuse. Use with adequate ventilation. Do not get in eyes, on skin, or on clothing. Do not ingest or inhale. Use only in a chemical fume hood.
Protection
Eyes: Wear appropriate protective eyeglasses or chemical safety goggles as described by OSHA's eye and face protection regulations in 29 CFR 1910.133 or European Standard EN166. Skin: Wear appropriate protective gloves to prevent skin exposure. Clothing: Wear appropriate protective clothing to prevent skin exposure.
Respirators
Follow the OSHA respirator regulations found in 29CFR 1910.134 or European Standard EN 149. Always use a NIOSH or European Standard EN 149 approved respirator when necessary.
Small spills/leaks
Vacuum or sweep up material and place into a suitable disposal container.
Stability
Stable under normal shipping and handling conditions.
Incompatibilities
Strong reducing agents - organic materials - finely powdered metals.
Decomposition
Selenium/selenium oxides.

Fire.
Fire fighting
Wear a self-contained breathing apparatus in pressure-demand, MSHA/NIOSH (approved or equivalent), and full protective gear. Extinguishing media: For small fires, use dry chemical, carbon dioxide, water spray or alcohol-resistant foam.
Fire potential
Non-combustible, substance itself does not burn but may decompose upon heating to produce corrosive and/or toxic fumes.
Hazards
When heated to decomposition it emits toxic fumes of selenium. Avoid heating.
Combustion products
Fire may produce irritating, corrosive and/or toxic gases.

Health.
Exposure limit(s)
TLV (as Se): ppm; 0.2 mg/m3 (ACGIH 1990-1991). PDK (as Se): 0.1 mg/m3 (USSR 1978).
Exposure effects
Prolonged or repeated skin contact may cause dermatitis. May cause liver and kidney damage. May cause reproductive and fetal effects. Chronic exposure to selenium may cause central nervous system effects, digestive tract disturbances, pallor, garlic breath,
   Ingestion
May be fatal if swallowed. May cause severe gastrointestinal tract irritation with nausea, vomiting and possible burns. May cause liver and kidney damage. May cause a garlic odor on the breath along with pallor, nervousness, depression, digestive tract disturbances and possilbe death.
   Inhalation
May cause severe irritation of the respiratory tract with sore throat, coughing, shortness of breath and delayed lung edema.
   Skin
May cause severe skin irritation. Prolonged and/or repeated contact may cause irritation and/or dermatitis.
   Eyes
May cause severe eye irritation. May result in corneal injury.

First aid
 
   Ingestion
If victim is conscious and alert, give 2-4 cupfuls of milk or water. Never give anything by mouth to an unconscious person. Get medical aid immediately.
   Inhalation
Get medical aid immediately. Remove from exposure to fresh air immediately. If not breathing, give artificial respiration. If breathing is difficult, give oxygen.
   Skin
Get medical aid immediately. Immediately flush skin with plenty of soap and water for at least 15 minutes while removing contaminated clothing and shoes.
   Eyes
Immediately flush eyes with plenty of water for at least 15 minutes, occasionally lifting the upper and lower eyelids. Get medical aid immediately.

Transport.
UN number
2811
Response guide
Hazard class
6.1
Packing Group
I; II; III
 
USCG CHRIS Code
SEA