Sulfur dioxide

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 InChI=1S/O2S/c1-3-2 Key: RAHZWNYVWXNFOC-UHFFFAOYSA-N ; InChI=1/O2S/c1-3-2 Key: RAHZWNYVWXNFOC-UHFFFAOYAT;
	SMILES O=S=O;
Properties
Chemical formula	SO; 2
Molar mass	64.066 g/mol
Appearance	Colorless and pungent gas
Odor	Pungent; similar to a just-struck match
Density	2.619 kg m−3
Melting point	−72 °C; −98 °F; 201 K
Boiling point	−10 °C (14 °F; 263 K)
Solubility in water	94 g/L; 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
Acidity (pKa)	~1.81
Basicity (pKb)	~12.19
Magnetic susceptibility (χ)	−18.2·10−6 cm3/mol
Viscosity	12.82 μPa·s
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
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)
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)
	NIOSH (US health exposure limits):
PEL (Permissible)	TWA 5 ppm (13 mg/m3)
REL (Recommended)	TWA 2 ppm (5 mg/m3) ST 5 ppm (13 mg/m3)
IDLH (Immediate danger)	100 ppm
Related compounds
Related sulfur oxides	Sulfur monoxide; Sulfur trioxide; Disulfur monoxide
Related compounds	Ozone; Selenium dioxide; Sulfurous acid; Tellurium dioxide; Polonium 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 S O
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.^[9] It was known to alchemists as "volatile spirit of sulfur" since at least 16th century.^[10]

^ Sulfur dioxide Archived 2019-12-30 at the Wayback Machine, U.S. National Library of Medicine
^ "Sulfur Dioxide". Archived from the original on 2023-09-24. Retrieved 2024-03-22., U.S. National Library of Medicine
^ Lide DR, ed. (2006). CRC Handbook of Chemistry and Physics (87th ed.). Boca Raton, FL: CRC Press. ISBN 0-8493-0487-3.
^ "Hazardous Substances Data Bank".
^ Miller J Jr, Shah P, Yaws C (1976). "Correlation constants for chemical compounds". Chemical Engineering. 83 (25): 153–180. ISSN 0009-2460.
^ "C&L Inventory".
^ ^a ^b ^c NIOSH Pocket Guide to Chemical Hazards. "#0575". National Institute for Occupational Safety and Health (NIOSH).
^ ^a ^b "Sulfur dioxide". Immediately Dangerous to Life or Health Concentrations (IDLH). National Institute for Occupational Safety and Health (NIOSH).
^ Cite error: The named reference Greenwood was invoked but never defined (see the help page).
^ Wothers P (2019). Antimony, Gold, and Jupiter's Wolf: How the Elements Were Named. Oxford University Press. ISBN 978-0-19-965272-3.

[1] Sulfur dioxide Archived 2019-12-30 at the Wayback Machine, U.S. National Library of Medicine

[2] "Sulfur Dioxide". Archived from the original on 2023-09-24. Retrieved 2024-03-22., U.S. National Library of Medicine

[3] Lide DR, ed. (2006). CRC Handbook of Chemistry and Physics (87th ed.). Boca Raton, FL: CRC Press. ISBN 0-8493-0487-3.

[4] "Hazardous Substances Data Bank".

[5] Miller J Jr, Shah P, Yaws C (1976). "Correlation constants for chemical compounds". Chemical Engineering. 83 (25): 153–180. ISSN 0009-2460.

[6] "C&L Inventory".

[PGCH-7] NIOSH Pocket Guide to Chemical Hazards. "#0575". National Institute for Occupational Safety and Health (NIOSH).

[IDLH-8] "Sulfur dioxide". Immediately Dangerous to Life or Health Concentrations (IDLH). National Institute for Occupational Safety and Health (NIOSH).

[Greenwood-9] Cite error: The named reference Greenwood was invoked but never defined (see the help page).

[:1-10] Wothers P (2019). Antimony, Gold, and Jupiter's Wolf: How the Elements Were Named. Oxford University Press. ISBN 978-0-19-965272-3.

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Names



IUPAC name Sulfur dioxide
Other names Sulfurous anhydride Sulfur(IV) oxide
Identifiers
CAS Number	7446-09-5^Y
3D model (JSmol)	Interactive image
Beilstein Reference	3535237
ChEBI	CHEBI:18422^Y
ChEMBL	ChEMBL1235997^N
ChemSpider	1087^Y
ECHA InfoCard	100.028.359
EC Number	231-195-2
E number	E220 (preservatives)
Gmelin Reference	1443
KEGG	D05961^Y
MeSH	Sulfur+dioxide
PubChem CID	1119
RTECS number	WS4550000
UNII	0UZA3422Q4^Y
UN number	1079, 2037
CompTox Dashboard (EPA)	DTXSID6029672
InChI InChI=1S/O2S/c1-3-2^Y Key: RAHZWNYVWXNFOC-UHFFFAOYSA-N^Y InChI=1/O2S/c1-3-2 Key: RAHZWNYVWXNFOC-UHFFFAOYAT
SMILES O=S=O
Properties
Chemical formula	SO ₂
Molar mass	64.066 g/mol
Appearance	Colorless and pungent gas
Odor	Pungent; similar to a just-struck match^[1]
Density	2.619 kg m⁻³^[2]
Melting point	−72 °C; −98 °F; 201 K
Boiling point	−10 °C (14 °F; 263 K)
Solubility in water	94 g/L^[3] 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^[4]
Acidity (pK_a)	~1.81
Basicity (pK_b)	~12.19
Magnetic susceptibility (χ)	−18.2·10⁻⁶ cm³/mol
Viscosity	12.82 μPa·s^[5]
Structure
Point group	C_2v
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 (Δ_fH^⦵₂₉₈)	−296.81 kJ mol⁻¹
Hazards
GHS labelling:
Pictograms
Signal word	Danger
Hazard statements	H314, H331^[6]
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)^[8]
LC_Lo (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)^[8]
NIOSH (US health exposure limits):
PEL (Permissible)	TWA 5 ppm (13 mg/m³)^[7]
REL (Recommended)	TWA 2 ppm (5 mg/m³) ST 5 ppm (13 mg/m³)^[7]
IDLH (Immediate danger)	100 ppm^[7]
Related compounds
Related sulfur oxides	Sulfur monoxide Sulfur trioxide Disulfur monoxide
Related compounds	Ozone Selenium dioxide Sulfurous acid Tellurium dioxide Polonium dioxide
Except where otherwise noted, data are given for materials in their standard state (at 25 °C [77 °F], 100 kPa). N verify (what is ^YN ?) Infobox references