Vinyl group
In chemistry, vinyl or ethenyl (abbreviated as Vi) is the functional group with the formula H-C=CH. It is the ethylene (IUPAC ethene) molecule (HC=CH) with one fewer hydrogen atom. The name is also used for any compound containing that group, namely R−CH=CH where R is any other group of atoms. An industrially important example is vinyl chloride, precursor to PVC, a plastic commonly known as "vinyl". Vinyl is one of the alkenyl functional groups. On a carbon skeleton, sp-hybridized carbons or positions are often called vinylic. Allyls, acrylates and styrenics  contain vinyl groups. (A styrenic crosslinker with two vinyl groups is called "divinyl benzene".) Vinyl polymers. Vinyl groups can polymerize with the aid of a radical initiator or a catalyst, forming vinyl polymers. Vinyl polymers contain no vinyl groups. Instead they are saturated. The following table gives some examples of vinyl polymers. Reactivity. Vinyl derivatives are alkenes. If activated by an adjacent group, the increased polarization of the bond gives rise to characteristic reactivity, which is termed vinylogous: Vinyl organometallics, e.g. vinyllithium and vinyl tributyltin, participate in coupling reactions such as in Negishi coupling. Etymology. The etymology of "vinyl" is  the Latin "vinum" = "wine", and the Greek word "hylos" 'υλος (matter or material), because of its relationship with ethyl alcohol. The term "vinyl" was coined by the German chemist Hermann Kolbe in 1851.