:2,2'-Bithiophene

{{Chembox

| ImageFile = 2,2'Bithiophene.png

| ImageSize =

| ImageFile1 = 2,2'-Bithiophene.jpg

| PIN = 2,2′-Bithiophene

| OtherNames = 2,2′-Bisthiophene, 2,2′-dithienyl, 2,2′-bithienyl, 2-(2-thienyl)thiophene

|Section1={{Chembox Identifiers

| CASNo = 492-97-7

| UNII_Ref = {{fdacite|correct|FDA}}

| UNII = 8CTS9HJ7L6

| EINECS = 207-767-2

| PubChem = 68120

| ChemSpiderID = 61428

| SMILES = c1cc(sc1)c2cccs2

| InChI = 1/C8H6S2/c1-3-7(9-5-1)8-4-2-6-10-8/h1-6H

| InChIKey = OHZAHWOAMVVGEL-UHFFFAOYAB

| StdInChI = 1S/C8H6S2/c1-3-7(9-5-1)8-4-2-6-10-8/h1-6H

| StdInChIKey = OHZAHWOAMVVGEL-UHFFFAOYSA-N }}

|Section2={{Chembox Properties

| C=8|H=6|S=2

| MolarMass =

| Appearance = Colorless crystals

| Density = 1.44 g/cm³

| MeltingPtC = 31.1

| MeltingPt_ref={{cite book |ref=Haynes| editor= Haynes, William M. | date = 2016| title = CRC Handbook of Chemistry and Physics | edition = 97th | publisher = CRC Press | isbn = 9781498754293| page=3.58}}

| BoilingPtC = 260

| BoilingPt_ref=

| Solubility = }}

|Section3={{Chembox Structure

| Structure_ref = {{cite journal|doi=10.1107/S010827019301011X |title=Bithiophene at 133 K |date=1994 |last1=Pelletier |first1=M. |last2=Brisse |first2=F. |journal=Acta Crystallographica Section C Crystal Structure Communications |volume=50 |issue=12 |pages=1942–1945 }}

| CrystalStruct = Monoclinic

| SpaceGroup = P2₁/c

| LattConst_a = 7.873 A

| LattConst_b = 5.771 A

| LattConst_c = 8.813 A

| LattConst_alpha =

| LattConst_beta = 107.07

| Coordination = 2

}}

|Section4={{Chembox Hazards

| MainHazards =

| FlashPt =

| AutoignitionPt = }}

}}

2,2′-Bithiophene is the organic compound. It is a colorless solid, although commercial samples are often greenish.{{cite journal|author1=Chaloner, P. A.|author2= Gunatunga, S. R.|author3= Hitchcock, P. B. |title=Redetermination of 2,2′-bithiophene |journal=Acta Crystallographica C|year=1994|volume=C50|issue= 12|pages= 1941–2|doi=10.1107/S0108270194001149}} It is the most common of the three isomers with formula (C₄H₃S)₂. The other two isomers have the connectivity 2,3′- and 3,3′-. The compound is typically prepared by cross-coupling starting from 2-halothiophenes.

X-ray crystallography shows that the two rings are coplanar, unlike the situation for biphenyl.