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Especially in proteins, electron transfer often involves hopping of an electron from one redox-active center to another one. The hopping pathway, which can be viewed as a vector, guides and facilitates ET within an insulating matrix. Typical redox centers are iron-sulfur clusters, e.g. the 4Fe-4S ferredoxins. These sites are often separated by ...
Redox reactions can occur slowly, as in the formation of rust, or rapidly, as in the case of burning fuel. Electron transfer reactions are generally fast, occurring within the time of mixing. [20] The mechanisms of atom-transfer reactions are highly variable because many kinds of atoms can be transferred.
An electron transport chain (ETC [1]) is a series of protein complexes and other molecules which transfer electrons from electron donors to electron acceptors via redox reactions (both reduction and oxidation occurring simultaneously) and couples this electron transfer with the transfer of protons (H + ions) across a membrane.
Elementary steps like proton coupled electron transfer and the movement of electrons between an electrode and substrate are special to electrochemical processes. . Electrochemical mechanisms are important to all redox chemistry including corrosion, redox active photochemistry including photosynthesis, other biological systems often involving electron transport chains and other forms of ...
In electrochemistry, the Nernst equation is a chemical thermodynamical relationship that permits the calculation of the reduction potential of a reaction (half-cell or full cell reaction) from the standard electrode potential, absolute temperature, the number of electrons involved in the redox reaction, and activities (often approximated by concentrations) of the chemical species undergoing ...
n = number of electrons transferred in the redox event (usually 1) A = electrode area in cm 2; F = Faraday constant in C mol −1; D = diffusion coefficient in cm 2 /s; C = concentration in mol/cm 3; ν = scan rate in V/s; R = Gas constant in J K −1 mol −1; T = temperature in K; The constant with a value of 2.69×10 5 has units of C mol − ...
In aqueous solutions, redox potential is a measure of the tendency of the solution to either gain or lose electrons in a reaction. A solution with a higher (more positive) reduction potential than some other molecule will have a tendency to gain electrons from this molecule (i.e. to be reduced by oxidizing this other molecule) and a solution with a lower (more negative) reduction potential ...
In outer sphere redox reactions no bonds are formed or broken; only an electron transfer (ET) takes place. A quite simple example is the Fe 2+ /Fe 3+ redox reaction, the self exchange reaction which is known to be always occurring in an aqueous solution containing the aquo complexes [Fe(H 2 O) 6] 2+ and [Fe(H 2 O)6] 3+.