09-05-2023-2036 - draft (Sulfur dioxide (IUPAC-recommended spelling) or sulphur dioxide (traditional Commonwealth English), etc., draft)

Sulfur dioxide

Names
IUPAC name Sulfur dioxide
Other names Sulfurous anhydride Sulfur(IV) oxide
Identifiers
CAS Number	7446-09-5
3D model (JSmol)	Interactive image
Beilstein Reference	3535237
ChEBI	CHEBI:18422
ChEMBL	ChEMBL1235997
ChemSpider	1087
ECHA InfoCard	100.028.359
EC Number	231-195-2
E number	E220 (preservatives)
Gmelin Reference	1443
KEGG	D05961
MeSH	Sulfur+dioxide
PubChem CID	1119
RTECS number	WS4550000
UNII	0UZA3422Q4
UN number	1079, 2037
CompTox Dashboard (EPA)	DTXSID6029672

InChI

SMILES
Properties
Chemical formula	SO 2
Molar mass	64.066 g mol−1
Appearance	Colorless and pungent gas
Odor	Pungent; similar to a just-struck match[1]
Density	2.6288 kg m−3[citation needed]
Melting point	−72 °C; −98 °F; 201 K
Boiling point	−10 °C (14 °F; 263 K)
Solubility in water	94 g/L[2] forms sulfurous acid
Vapor pressure	230 kPa at 10 °C; 330 kPa at 20 °C; 462 kPa at 30 °C; 630 kPa at 40 °C[3]
Acidity (pKa)	~1.81
Basicity (pKb)	~12.19
Magnetic susceptibility (χ)	−18.2·10−6 cm3/mol
Viscosity	12.82 μPa·s[4]
Structure
Point group	C2v
Coordination geometry	Digonal
Molecular shape	Dihedral
Dipole moment	1.62 D
Thermochemistry
Std molar entropy (S⦵298)	248.223 J K−1 mol−1
Std enthalpy of formation (ΔfH⦵298)	−296.81 kJ mol−1
Hazards
GHS labelling:
Pictograms
Signal word	Danger
Hazard statements	H314, H331[5]
NFPA 704 (fire diamond)	3 0 0
Lethal dose or concentration (LD, LC):
LC50 (median concentration)	3000 ppm (mouse, 30 min) 2520 ppm (rat, 1 hr)[7]
LCLo (lowest published)	993 ppm (rat, 20 min) 611 ppm (rat, 5 hr) 764 ppm (mouse, 20 min) 1000 ppm (human, 10 min) 3000 ppm (human, 5 min)[7]
NIOSH (US health exposure limits):
PEL (Permissible)	TWA 5 ppm (13 mg/m3)[6]
REL (Recommended)	TWA 2 ppm (5 mg/m3) ST 5 ppm (13 mg/m3)[6]
IDLH (Immediate danger)	100 ppm[6]
Related compounds
Related sulfur oxides	Sulfur monoxide Sulfur trioxide Disulfur monoxide
Related compounds	Ozone Selenium dioxide Sulfurous acid Tellurium dioxide
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

Sulfur dioxide (IUPAC-recommended spelling) or sulphur dioxide (traditional Commonwealth English) is the chemical compound with the formula SO
₂. It is a toxic gas responsible for the odor of burnt matches. It is released naturally by volcanic activity and is produced as a by-product of copper extraction and the burning of sulfur-bearing fossil fuels.^[8] 

https://en.wikipedia.org/wiki/Sulfur_dioxide