Selenium dioxide

Selenium dioxide
Names
	Other names Selenium(IV) oxide; Selenous anhydride
Identifiers
CAS Number	7446-08-4 ;
3D model (JSmol)	monomer: Interactive image; polymer: Interactive image;
ChEMBL	ChEMBL3183452;
ChemSpider	22440 ;
ECHA InfoCard	100.028.358
EC Number	231-194-7;
PubChem CID	24007;
RTECS number	VS8575000;
UNII	9N3UK29E57 ;
UN number	3283
CompTox Dashboard (EPA)	DTXSID4021264 ;
	InChI InChI=1S/O2Se/c1-3-2 Key: JPJALAQPGMAKDF-UHFFFAOYSA-N ; InChI=1/O2Se/c1-3-2 Key: JPJALAQPGMAKDF-UHFFFAOYAQ;
	SMILES monomer: O=[Se]=O; polymer: O[Se](=O)O[Se](=O)O[Se](=O)O[Se](=O)O[Se](=O)O[Se](=O)O[Se](=O)O[Se](=O)O[Se](=O)O[Se](=O)O[Se](=O)O[Se](=O)O[Se](=O)O[Se](=O)O[Se](=O)O;
Properties
Chemical formula	SeO2
Molar mass	110.96 g/mol
Appearance	White crystals, turn slightly pink with trace decomposition
Odor	rotten radishes
Density	3.954 g/cm3, solid
Melting point	340 °C (644 °F; 613 K) (sealed tube)
Boiling point	350 °C (662 °F; 623 K) subl.
Solubility in water	38.4 g/100 mL (20 °C) ; 39.5 g/100 ml (25 °C) ; 82.5 g/100 mL (65 °C)
Solubility	soluble in benzene
Solubility in ethanol	6.7 g/100 mL (15 °C)
Solubility in acetone	4.4 g/100 mL (15 °C)
Solubility in acetic acid	1.11 g/100 mL (14 °C)
Solubility in methanol	10.16 g/100 mL (12 °C)
Vapor pressure	1.65 kPa (70 °C)
Acidity (pKa)	2.62; 8.32
Magnetic susceptibility (χ)	−27.2·10−6 cm3/mol
Refractive index (nD)	> 1.76
Structure
Crystal structure	see text
Coordination geometry	trigonal (Se)
Hazards
	Occupational safety and health (OHS/OSH):
Main hazards	Toxic by ingestion and inhalation
	GHS labelling:
Pictograms
Signal word	Danger
Hazard statements	H301, H331, H373, H410
Precautionary statements	P260, P261, P264, P270, P271, P273, P301+P310, P304+P340, P311, P314, P321, P330, P391, P403+P233, P405, P501
NFPA 704 (fire diamond)	3 0 0
Flash point	Non-flammable
	Lethal dose or concentration (LD, LC):
LCLo (lowest published)	5890 mg/m3 (rabbit, 20 min); 6590 mg/m3 (goat, 10 min); 6590 mg/m3 (sheep, 10 min)
Safety data sheet (SDS)	ICSC 0946
Related compounds
Other anions	Selenium disulfide
Other cations	Sulfur dioxide; Tellurium dioxide
Related selenium oxides	Selenium trioxide
Related compounds	Selenous acid
	Except where otherwise noted, data are given for materials in their standard state (at 25 °C [77 °F], 100 kPa). verify (what is ?) Infobox references

Selenium dioxide is the chemical compound with the formula SeO₂. This colorless solid is one of the most frequently encountered compounds of selenium. It is used in making specialized glasses as well as a reagent in organic chemistry.^[4]

^ "Safety data sheet: Selenium dioxide" (PDF). integrachem.com. 27 March 2015. Retrieved 2022-12-02.
^ "Selenium dioxide safety and hazards". pubchem.ncbi.nlm.nih.gov. Retrieved 2022-12-02.
^ "Selenium compounds (as Se)". Immediately Dangerous to Life or Health Concentrations (IDLH). National Institute for Occupational Safety and Health (NIOSH).
^ Hoekstra, William J.; Fairlamb, Ian J. S.; Giroux, Simon; Chen, Yuzhong (2017). "Selenium(IV) Oxide". Encyclopedia of Reagents for Organic Synthesis. pp. 1–12. doi:10.1002/047084289X.rs008.pub3. ISBN 978-0-470-84289-8.

[msds-1] "Safety data sheet: Selenium dioxide" (PDF). integrachem.com. 27 March 2015. Retrieved 2022-12-02.

[2] "Selenium dioxide safety and hazards". pubchem.ncbi.nlm.nih.gov. Retrieved 2022-12-02.

[3] "Selenium compounds (as Se)". Immediately Dangerous to Life or Health Concentrations (IDLH). National Institute for Occupational Safety and Health (NIOSH).

[4] Hoekstra, William J.; Fairlamb, Ian J. S.; Giroux, Simon; Chen, Yuzhong (2017). "Selenium(IV) Oxide". Encyclopedia of Reagents for Organic Synthesis. pp. 1–12. doi:10.1002/047084289X.rs008.pub3. ISBN 978-0-470-84289-8.

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Names



Other names Selenium(IV) oxide Selenous anhydride
Identifiers
CAS Number	7446-08-4^Y
3D model (JSmol)	monomer: Interactive image polymer: Interactive image
ChEMBL	ChEMBL3183452
ChemSpider	22440^Y
ECHA InfoCard	100.028.358
EC Number	231-194-7
PubChem CID	24007
RTECS number	VS8575000
UNII	9N3UK29E57^Y
UN number	3283
CompTox Dashboard (EPA)	DTXSID4021264
InChI InChI=1S/O2Se/c1-3-2^Y Key: JPJALAQPGMAKDF-UHFFFAOYSA-N^Y InChI=1/O2Se/c1-3-2 Key: JPJALAQPGMAKDF-UHFFFAOYAQ
SMILES monomer: O=[Se]=O polymer: O[Se](=O)O[Se](=O)O[Se](=O)O[Se](=O)O[Se](=O)O[Se](=O)O[Se](=O)O[Se](=O)O[Se](=O)O[Se](=O)O[Se](=O)O[Se](=O)O[Se](=O)O[Se](=O)O[Se](=O)O
Properties
Chemical formula	SeO₂
Molar mass	110.96 g/mol
Appearance	White crystals, turn slightly pink with trace decomposition^[1]
Odor	rotten radishes
Density	3.954 g/cm³, solid
Melting point	340 °C (644 °F; 613 K) (sealed tube)
Boiling point	350 °C (662 °F; 623 K) subl.
Solubility in water	38.4 g/100 mL (20 °C) 39.5 g/100 ml (25 °C) 82.5 g/100 mL (65 °C)
Solubility	soluble in benzene
Solubility in ethanol	6.7 g/100 mL (15 °C)
Solubility in acetone	4.4 g/100 mL (15 °C)
Solubility in acetic acid	1.11 g/100 mL (14 °C)
Solubility in methanol	10.16 g/100 mL (12 °C)
Vapor pressure	1.65 kPa (70 °C)
Acidity (pK_a)	2.62; 8.32
Magnetic susceptibility (χ)	−27.2·10⁻⁶ cm³/mol
Refractive index (n_D)	> 1.76
Structure
Crystal structure	see text
Coordination geometry	trigonal (Se)
Hazards
Occupational safety and health (OHS/OSH):
Main hazards	Toxic by ingestion and inhalation^[2]
GHS labelling:
Pictograms
Signal word	Danger
Hazard statements	H301, H331, H373, H410
Precautionary statements	P260, P261, P264, P270, P271, P273, P301+P310, P304+P340, P311, P314, P321, P330, P391, P403+P233, P405, P501
NFPA 704 (fire diamond)	3 0 0
Flash point	Non-flammable
Lethal dose or concentration (LD, LC):
LC_Lo (lowest published)	5890 mg/m³ (rabbit, 20 min) 6590 mg/m³ (goat, 10 min) 6590 mg/m³ (sheep, 10 min)^[3]
Safety data sheet (SDS)	ICSC 0946
Related compounds
Other anions	Selenium disulfide
Other cations	Sulfur dioxide Tellurium dioxide
Related selenium oxides	Selenium trioxide
Related compounds	Selenous acid
Except where otherwise noted, data are given for materials in their standard state (at 25 °C [77 °F], 100 kPa). Y verify (what is ^YN ?) Infobox references