Structure of Double Bond

Carbons in the double bond of butene are sp² hybridized. Side on p-p orbital overlap creates a π-bond. Angles around the carbons in the double bond are ~ 120º. Thus, all of the atoms bonded to the sp² hybridized carbon lie in a plane. Carbon-Carbon double bond length is ~ 1.34 Å (single bonds in alkane are ~ 1.54 Å.

Alkenes are readily attacked by reagents or compounds which are in search of electrons. Such reagents are called electrophiles or electrophilic reagents. Further, the presence of π-bond makes alkenes less stable and more reactive than alkanes and hence readily change into compounds containing single bonds by adding electrophilic reagents.

Alkenes are part of an homologous series. They have the functional group of a C=C (double bond between two carbons) and the general formula of CnH₂n, where n is the number of carbon molecules.

There are two types of bonds in alkenes because of the different electron sub-shells.

· σ bond (sigma)

· π bond (pi)

There is a σ bond (sigma) which is when two p sub orbitals overlap, and the π bond (pi) is above and below the atoms, it tends to be weaker because of this and it also has no rotation which is why isomerism exists. Because of this bonding, the double bond is a center of high electron density, meaning it is a great place for electrophiles to attack.