thiirene
{{chembox
| Verifiedfields = changed
| Watchedfields = changed
| verifiedrevid = 448762476
| ImageFile=Thiiren.png
| ImageSize=80px
| PIN=Thiirene
| SystematicName = Thiacyclopropene
| OtherNames=Epithioethene
Ethyne sulfide
Acetylene sulfide
|Section1={{Chembox Identifiers
| CASNo=157-20-0
| PubChem=5461041
| SMILES=C1=CS1
| ChemSpiderID_Ref = {{chemspidercite|correct|chemspider}}
| ChemSpiderID = 4574411
| InChI = 1/C2H2S/c1-2-3-1/h1-2H
| InChIKey = JTQAPFZZCXWQNQ-UHFFFAOYAN
| StdInChI_Ref = {{stdinchicite|changed|chemspider}}
| StdInChI = 1S/C2H2S/c1-2-3-1/h1-2H
| StdInChIKey_Ref = {{stdinchicite|changed|chemspider}}
| StdInChIKey = JTQAPFZZCXWQNQ-UHFFFAOYSA-N
| MeSHName =
| ChEBI_Ref = {{ebicite|correct|EBI}}
| ChEBI = 30976
| Beilstein = 1304471
| Gmelin = 239545
}}
|Section2={{Chembox Properties
| Formula=C2H2S
| MolarMass=58.10228
| Appearance=
| Density=
| MeltingPt=
| BoilingPt=
| Solubility=
}}
}}
Thiirene is an organosulfur compound with the formula C2H2S. It can be viewed as a derivative of cyclopropene, but with the methylene group replaced by sulfur. It is antiaromatic and very labile.{{cite book |doi=10.1016/B978-008096518-5.00005-8|chapter=Thiiranes and Thiirenes: Monocyclic|title=Comprehensive Heterocyclic Chemistry II|year=1996|last1=Ando|first1=Wataru|last2=Choi|first2=Nami|last3=Tokitoh|first3=Norihiro|pages=173–240|isbn=9780080965185}}
Thiirenes and derivatives
No thiirene has been isolated at room temperature, but they have been observed spectroscopically at low temperatures.{{cite journal |doi=10.1021/jo00406a045|title=Low-Temperature Matrix Isolation of Thiirenes|year=1978|last1=Torres|first1=M.|last2=Clement|first2=A.|last3=Bertie|first3=J. E.|last4=Gunning|first4=H. E.|last5=Strausz|first5=O. P.|journal=The Journal of Organic Chemistry|volume=43|issue=12|pages=2490–2493}}
Thiirene-S-oxides and S-alkylthiirenium salts have been characterized by X-ray crystallography.{{cite journal |doi=10.1021/jo991731o|title=X-ray Structures and Anionotropic Rearrangements of Di-tert-butyl-Substituted Thiiranium and Thiirenium Ions. A Structure−Reactivity Relationship|year=2000|last1=Destro|first1=Riccardo|last2=Lucchini|first2=Vittorio|last3=Modena|first3=Giorgio|last4=Pasquato|first4=Lucia|journal=The Journal of Organic Chemistry|volume=65|issue=11|pages=3367–3370|pmid=10843618}}