Double bond

Other common double bonds are found in azo compounds (N=N), imines (C=N), and sulfoxides (S=O).

In a skeletal formula, a double bond is drawn as two parallel lines (=) between the two connected atoms; typographically, the equals sign is used for this.

[1][2] Double bonds were introduced in chemical notation by Russian chemist Alexander Butlerov.

Double bonds are also electron-rich, which makes them potentially more reactive in the presence of a strong electron acceptor (as in addition reactions of the halogens).

Double bonded compounds, alkene homologs, R2E=ER2 are now known for all of the heavier group 14 elements.

Unlike the alkenes these compounds are not planar but adopt twisted and/or trans bent structures.

The distannene (Me3Si)2CHSn=SnCH(SiMe3)2 has a tin-tin bond length just a little shorter than a single bond, a trans bent structure with pyramidal coordination at each tin atom, and readily dissociates in solution to form (Me3Si)2CHSn: (stannanediyl, a carbene analog).