Kaksoisidoksia

Kaksoisidoksia, or double bonds, are a type of covalent chemical bond in which two electron pairs are shared between two atoms. This results in a stronger and shorter bond compared to a single covalent bond, where only one electron pair is shared. Double bonds are commonly found in organic molecules, particularly in unsaturated hydrocarbons like alkenes, which contain at least one carbon-carbon double bond.

The presence of a double bond affects the molecule's geometry and reactivity. In an alkene, the atoms involved in the double bond lie in a planar arrangement, and rotation around the bond is restricted. This restricted rotation can lead to the existence of isomers, known as cis-trans isomers, where different spatial arrangements of substituents around the double bond are possible.

The pi (π) component of the double bond is less shielded than the sigma (σ) bond, making it more susceptible to attack by electrophiles. This characteristic makes double bonds sites of higher reactivity in many chemical reactions, such as addition reactions. For example, alkenes readily undergo hydrogenation, halogenation, and hydration reactions across the double bond. The degree of unsaturation in a molecule can be determined by the number of double and triple bonds it contains. Understanding double bonds is fundamental to comprehending the structure, properties, and reactions of a vast array of chemical compounds.