Oxidizers & Peroxides
REACH
Selenium dioxide
CAS Number
7446-08-4
EC Number
231-194-7
Abbreviation
SeO2
What is Selenium dioxide?
Selenium dioxide (CAS 7446-08-4), also known as selenious anhydride, is an inorganic oxidizing agent used primarily as a catalyst and reagent in chemical synthesis and industrial refining.
Where is Selenium dioxide used?
- Organic synthesis: reagent for allylic and benzylic oxidations, converting methylene groups to carbonyl compounds in pharmaceutical and fine chemical intermediates
- Electronics: component in glass and ceramic formulations where controlled selenium incorporation modifies optical and electrical properties
- Metallurgy and mining: refining agent for copper and other non-ferrous metals, removing impurities during electrorefining
- It also serves as a precursor in the production of other selenium compounds for pigment and catalyst manufacturing.
Good to know: Selective oxidation reactions are difficult to achieve with conventional oxidants. Handling requirements reflect its oxidizing classification.
Commercial specifications
- Purity levels typically ranging from 99% upward
- Packaging from small quantities for research use to bulk quantities for industrial procurement
Other Names (Synonyms)
Selenous anhydride|Selenium(IV) oxide|Selenious anhydride|Selenium oxide (SeO2)|Selenium dioxide dimer|Selenous acid anhydride|Selenium(IV) dioxide (1:2)|Selenium oxide (Se2O4)|SeO2
What are the physical properties of Selenium dioxide?
Melting Point 340 °C
Boiling Point 684.9 °C(lit.)
Density 3.954 g/cm³ @ Temp: 15 °C
Flash Point 315°C
Appearance Selenium dioxide is white to slightly reddish crystalline solid or yellow liquid which forms a yellowgreen vapor. It has a sour and pungent odor. Odor threshold in air50.0002 milligram per cubic meter.
Color white
Form powder
Water Solubility 38.4 g/100 mL (14 ºC)
Vapor Pressure 1 mm Hg ( 157 °C)
Refractive Index nD20 <1.76
pH 2 (10g/l, H2O, 20℃)
How is Selenium dioxide classified and handled safely? Learn More
Danger
GHS05· Corrosive GHS06· Toxic GHS08· Health Hazard GHS09· Environmental Hazard GHS07· Irritant
Hazard Statements
H300 Fatal if swallowed
H301 Toxic if swallowed
H314 Causes severe skin burns and eye damage
H318 Causes serious eye damage
Precautionary Statements
P260 Do not breathe dust/fume/gas/mist/vapours/spray.
P261 Avoid breathing dust/fume/gas/mist/vapours/spray.
P264 Wash … thoroughly after handling.
P270 Do not eat, drink or smoke when using this product.
Which trade and regulatory codes apply to Selenium dioxide?
HS Code 28112900
UN Number 3440
ADR Class 6.1
Packing Group III
Storage Class 6.1C - Combustible acute toxic Cat.3
toxic compounds or compounds which causing chronic effects
WGK (Germany) 2