1,2-Difluoroethylene

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 cis-1,2-Difluoroethene (Z) Skeletal formula of trans-1,2-difluoroethene with all explicit hydrogens added trans-1,2-Difluoroethene (E)
3D structure of Cis-1,2-difluoroethene cis-1,2-Difluoroethene (Z) 3D structure of Trans-1,2-difluoroethene trans-1,2-Difluoroethene (E)
spacefill structure of Cis-1,2-difluoroethene cis-1,2-Difluoroethene (Z) 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
CAS Number	1630-77-9 (Z) Y
3D model (JSmol)	(cis): Interactive image (trans): Interactive image
ChemSpider	21106435
PubChem CID	5462921
InChI InChI=1S/C2H2F2/c3-1-2-4/h1-2H/b2-1- Key: WFLOTYSKFUPZQB-UPHRSURJSA-N
SMILES (cis): C(=C/F)/F (trans): C(=C/F)\F
Properties
Chemical formula	C2H2F2
Molar mass	64.035 g·mol−1
Boiling point	-36.0±8.0 °C
Magnetic susceptibility (χ)	-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). N verify (what is YN ?) Infobox references

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

For most 1,2-disubstituted compounds that exhibit cis–trans 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

• 1,1-Difluoroethylene
• Perfluoroisobutene

References

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.