Homologserie

Homologserie is a term used in organic chemistry to describe a series of organic compounds with the same general formula, in which each member differs from the next by a single repeating unit, typically a methylene group (CH2). These compounds possess similar chemical properties due to the presence of the same functional group, but their physical properties, such as boiling point and melting point, tend to change gradually and predictably with increasing molecular size.

The concept of homologserie was first introduced by the Swedish chemist Jöns Jacob Berzelius. The most well-known example of a homologserie is the alkane series, which includes methane (CH4), ethane (C2H6), propane (C3H8), and so on. Each successive alkane differs by a CH2 group. Other common homologserie include alkenes, alkynes, alcohols, and carboxylic acids.

The systematic naming of organic compounds often relies on the identification of the homologserie to which they belong. Understanding homologserie is fundamental to grasping the relationships between different organic molecules and predicting their reactivity and physical characteristics. This predictable pattern of variation within a series allows chemists to generalize properties and reactions, simplifying the study of a vast number of organic compounds.