Delokalisierte

Delokalisierte is a term used in German chemistry to describe systems in which electrons are delokalisiert across several atoms rather than being localized along individual bonds. The term stems from the verb delokalisieren, and is used chiefly as an attributive adjective (delokalisierte Elektronen, delokalisierte Systeme). In many modern texts, the more common spelling is delokalisiert, and the two forms are often treated as variants.

In chemistry, delokalisierte Elektronen are described by molecular orbital theory: electrons occupy orbitals that extend over an entire conjugated π-system, for example in benzene, allyl cation, or butadiene. This delokalisation stabilizes the system and accounts for characteristic properties such as resonance structures and aromaticity. The concept is closely related to resonance in valence-bond descriptions and to the idea of electron density that cannot be assigned to a single bond or atom.

Measurement and implications: Delokalisierte systems show distinct spectroscopic signatures (UV-Vis absorption bands) and specific NMR patterns. Computational methods quantify delokalisation through orbital coefficients, bond-order distributions, and resonance energy.

Usage: The term is used in German-language chemical literature but is less common than delokalisiert; equivalents in other languages include delocalized. See also delokalisation, resonance, aromaticity, and molecular orbital theory.