What is specifically defined as a double bond?

A double bond is characterized by the sharing of two pairs of electrons between two atoms. This means that each atom contributes one pair of electrons to create a bond, resulting in a stronger attraction compared to a single bond, which involves only one pair of electrons being shared.

In molecular structures, double bonds can significantly affect the geometry and reactivity of the molecules. For example, in carbon compounds, a double bond can restrict rotation around the bond axis due to the presence of two electron pairs, leading to different spatial arrangements of atoms. This is particularly important in organic chemistry, as it influences how molecules interact with one another.

Understanding the nature of a double bond is fundamental in both structural and molecular chemistry, as it plays a critical role in the properties and behaviors of various chemical compounds.