1,2-Difluoroethylene, also known as 1,2-difluoroethene, is an organofluoride with the molecular formula C2H2F2. It can exist as either of two geometric isomers, cis-1,2-difluoroethylene or trans-1,2-difluoroethylene.

1,2-Difluoroethylene
Skeletal formula of cis-1,2-difluoroethene with all explicit hydrogens added
Skeletal formula of cis-1,2-difluoroethene with all explicit hydrogens added
cis-1,2-Difluoroethene (Z)
Skeletal formula of trans-1,2-difluoroethene with all explicit hydrogens added
Skeletal formula of trans-1,2-difluoroethene with all explicit hydrogens added
trans-1,2-Difluoroethene (E)
3D structure of Cis-1,2-difluoroethene
3D structure of Cis-1,2-difluoroethene
cis-1,2-Difluoroethene (Z)
3D structure of Trans-1,2-difluoroethene
3D structure of Trans-1,2-difluoroethene
trans-1,2-Difluoroethene (E)
spacefill structure of Cis-1,2-difluoroethene
spacefill structure of Cis-1,2-difluoroethene
cis-1,2-Difluoroethene (Z)
spacefill structure of Tran-1,2-difluoroethene
spacefill structure of Tran-1,2-difluoroethene
trans-1,2-Difluoroethene (E)
Names
Preferred IUPAC name
1,2-Difluoroethene
Other names
1,2-Difluoroethylene
sym-Difluoroethylene
Ethene, 1,2-difluoro-,(Z)-
cis-Difluoroethene
Identifiers
3D model (JSmol)
ChemSpider
  • InChI=1S/C2H2F2/c3-1-2-4/h1-2H/b2-1-
    Key: WFLOTYSKFUPZQB-UPHRSURJSA-N
  • (cis): C(=C/F)/F
  • (trans): C(=C/F)\F
Properties
C2H2F2
Molar mass 64.035 g·mol−1
Boiling point -36.0±8.0 °C
-60.0·10−6 cm3/mol
Except where otherwise noted, data are given for materials in their standard state (at 25 °C [77 °F], 100 kPa).
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It is regarded as a hazardous chemical for being toxic by inhalation, and a volatile chemical, and it causes irritation when it comes into contact with the skin and mucous membranes.

E-Z relative stability

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For most 1,2-disubstituted compounds that exhibit cistrans isomerism, the trans (E) isomer is more stable than the cis (Z) isomer. However, 1,2-difluoroethylene has the opposite situation, with the cis more stable than the trans by 0.9 kcal/mol.[1]

See also

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References

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  1. ^ Craig, Norman C.; Entemann, Eric A. (July 1961). "Thermodynamics of cis-trans Isomerizations. The 1,2-Difluoroethylenes". Journal of the American Chemical Society. 83 (14): 3047–3050. doi:10.1021/ja01475a019.