Standard electrode potential (data page)

The data below tabulates standard electrode potentials (E°), in volts relative to the standard hydrogen electrode (SHE), at:

• Temperature ;
• Effective concentration (activity) 1 mol/L for each aqueous or amalgamated (mercury-alloyed) species;
• Unit activity for each solvent and pure solid or liquid species; and
• Absolute partial pressure for each gaseous reagent — the convention in most literature data but not the current standard state (100 kPa).

Variations from these ideal conditions affect measured voltage via the Nernst equation.

Electrode potentials of successive elementary half-reactions cannot be directly added. However, the corresponding Gibbs free energy changes (∆G°) can be added. Those free energy changes satisfy

where electrons are transferred, and the Faraday constant is the conversion factor describing Coulombs transferred per mole electrons. For example, from

the energy to form one neutral atom of Fe(s) from one Fe ion and two electrons is or 84 907 J/(mol ). That value is also the standard formation energy (∆G_f°) for an Fe ion, since and Fe(s) both have zero formation energy.

Data from different sources may cause table inconsistencies. For example: From additivity of Gibbs energies and canceling common factors, one must have But that equation does not hold exactly with the cited values.

Table of standard electrode potentials

Legend: (s) – solid; (l) – liquid; (g) – gas; (aq) – aqueous (default for all charged species); (Hg) – amalgam; bold – water electrolysis equations.

See also

• Galvanic series lists electrode potentials in saltwater
• Standard apparent reduction potentials in biochemistry at pH 7
• Reactivity series#Comparison with standard electrode potentials

Notes

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References

External links

• http://www.jesuitnola.org/upload/clark/Refs/red_pot.htm
• https://web.archive.org/web/20150924015049/http://www.fptl.ru/biblioteka/spravo4niki/handbook-of-Chemistry-and-Physics.pdf
• http://hyperphysics.phy-astr.gsu.edu/Hbase/tables/electpot.html#c1