A double bond is a type of chemical bond where two pairs of electrons are shared between two atoms. This bond is stronger than a single bond, which involves only one pair of shared electrons. Double bonds are commonly found in organic compounds, such as those containing the element carbon, and play a crucial role in determining the structure and reactivity of molecules. In molecular formulas, double bonds are often represented by two parallel lines (e.g., C=C). They can affect the physical properties of substances, such as boiling and melting points. Double bonds are also important in biological processes, including the formation of proteins and nucleic acids.