Elektronendonator

Elektronendonator is the German term for a substance that donates electrons in a redox (oxidation-reduction) reaction. In redox chemistry, an electron donor (reducing agent) is oxidized while the electron acceptor is reduced. The thermodynamic feasibility of the transfer is governed by the redox potentials of the involved couples; a larger difference between the acceptor’s tendency to gain electrons and the donor’s tendency to lose them drives the reaction.

In biology and biochemistry, common electron donors include NADH, NADPH and FADH2, which transfer electrons to respiratory or photosynthetic chains. Organic substrates such as glucose or glycerol can also act as donors during catabolic processes. In many bacteria and archaea, inorganic donors such as molecular hydrogen (H2), ferrous iron (Fe2+) or sulfide (S2−) provide electrons to external acceptors in anaerobic respiration or photosynthesis.

Thermodynamics aside, the strength of an electron donor is described by its redox potential and the related driving force ΔE°′ = E°′(acceptor) − E°′(donor). A more negative donor potential generally corresponds to a stronger reducing agent, though actual rates depend on kinetics, concentrations, pH and catalysts or enzymes present.

Applications span chemistry, biochemistry and materials science. Electron donors are central to energy metabolism, electrochemical synthesis, corrosion processes and various battery and fuel cell systems, where controlled electron transfer governs performance and efficiency.