Vinylgruppe

The vinyl group, known in German as vinylgruppe, is a functional group in organic chemistry with the formula -CH=CH2. It attaches to the rest of a molecule at the carbon of the double bond that bears one hydrogen. The group is derived from ethene by removing one hydrogen, giving the ethen-1-yl substituent in systematic nomenclature and vinyl in common usage.

The vinyl group is unsaturated and planar, with sp2-hybridized carbons. Its double bond makes it highly reactive toward electrophilic or radical addition reactions and enables polymerization. In many monomers the vinyl group participates in chain-growth polymerization, forming vinyl polymers such as polyvinyl chloride (PVC), polyvinyl acetate, and polystyrene (where the vinyl group is attached to a phenyl ring).

Common examples include vinyl chloride (the monomer for PVC), vinyl acetate, and styrene. The vinyl group also serves as a reactive handle in organic synthesis for cross-coupling and functionalization, conjoining with various functional groups to modify the properties of materials.

Nomenclature and language note: while "vinyl" is widely used as a substituent name, the systematic IUPAC name is ethen-1-yl. The term denotes the same -CH=CH2 fragment across contexts, from small molecules to polymers.

Safety: vinyl compounds can be hazardous; vinyl chloride is toxic and a suspected carcinogen. Appropriate handling and ventilation are required in industrial contexts.