What is Sulfur dioxide?
{{Chembox | Verifiedfields = changed | Watchedfields = changed | verifiedrevid = 477313199 | ImageFile = Sulfur-dioxide-2D.svg | ImageFile_Ref = {{chemboximage|correct|??}} | ImageSize = 160 | ImageName = Skeletal formula sulfur dioxide with assorted dimensions | ImageFile1 = Sulfur-dioxide-3D-vdW.png | ImageFile1_Ref = {{chemboximage|correct|??}} | ImageSize1 = 140 | ImageName1 = Spacefill model of sulfur dioxide | ImageFile2 = Sulfur dioxide lewis structure.png | ImageFile2_Ref = {{chemboximage|correct|??}} | ImageSize2 = 160 | ImageName2 = The Lewis structure of sulfur dioxide (SO2), showing unshared electron pairs. | IUPACName = Sulfur dioxide | OtherNames = Sulfurous anhydride<br/> Sulfur(IV) oxide |Section1={{Chembox Identifiers | CASNo = 7446-09-5 | CASNo_Ref = {{cascite|correct|CAS}} | PubChem = 1119 | ChemSpiderID = 1087 | ChemSpiderID_Ref = {{chemspidercite|correct|chemspider}} | UNII = 0UZA3422Q4 | UNII_Ref = {{fdacite|correct|FDA}} | EINECS = 231-195-2 | UNNumber = 1079, 2037 | KEGG = D05961 | KEGG_Ref = {{keggcite|correct|kegg}} | MeSHName = Sulfur+dioxide | ChEBI_Ref = {{ebicite|correct|EBI}} | ChEBI = 18422 | ChEMBL = 1235997 | ChEMBL_Ref = {{ebicite|changed|EBI}} | RTECS = WS4550000 | Beilstein = 3535237 | Gmelin = 1443 | SMILES = O=S=O | StdInChI = 1S/O2S/c1-3-2 | StdInChI_Ref = {{stdinchicite|correct|chemspider}} | InChI = 1/O2S/c1-3-2 | StdInChIKey = RAHZWNYVWXNFOC-UHFFFAOYSA-N | StdInChIKey_Ref = {{stdinchicite|correct|chemspider}} | InChIKey = RAHZWNYVWXNFOC-UHFFFAOYAT }} |Section2={{Chembox Properties | Formula = {{Chem|SO|2}} | MolarMass = 64.066 g mol<sup>−1</sup> | Appearance = Colorless gas | Density = 2.6288 kg m<sup>−3</sup> | Solubility = 94 g/L<ref>{{RubberBible87th}}</ref><br/>forms [[sulfurous acid]] | MeltingPtK = 201 | BoilingPtC = −10 | VaporPressure = 237.2 kPa | pKa = 1.81 | pKb = 12.19 | Viscosity = 0.403 cP (at 0&nbsp;°C) | Odor = Pungent; similar to a just-struck match<ref>[http://toxtown.nlm.nih.gov/text_version/chemicals.php?id=29 Sulfur dioxide] {{Webarchive|url=https://