substituen

A substituent is an atom or group of atoms that replaces a hydrogen atom in a parent molecule. This replacement occurs during a chemical reaction, often in organic chemistry. The nature of the substituent can significantly alter the physical and chemical properties of the parent molecule. For example, substituting a hydroxyl group (-OH) for a hydrogen atom in an alkane creates an alcohol, which has different properties like increased polarity and the ability to form hydrogen bonds.

Substituents are fundamental to understanding chemical structures and reactivity. They are often categorized based on their electronic effects, such as electron-donating groups (EDGs) or electron-withdrawing groups (EWGs). EDGs tend to increase electron density in the molecule, while EWGs decrease it. This influences how the molecule interacts with other chemical species. Common examples of substituents include halogens (like chlorine or bromine), alkyl groups (like methyl or ethyl), and functional groups (like nitro or amino). The position and type of substituents on a molecule are crucial for determining its overall behavior and potential applications. In nomenclature, substituents are often indicated by prefixes or suffixes.