The data below tabulates
standard electrode potentials (''E''°), in
volt
The volt (symbol: V) is the unit of electric potential, Voltage#Galvani potential vs. electrochemical potential, electric potential difference (voltage), and electromotive force in the International System of Units, International System of Uni ...
s relative to the
standard hydrogen electrode (SHE), at:
*
Temperature
Temperature is a physical quantity that quantitatively expresses the attribute of hotness or coldness. Temperature is measurement, measured with a thermometer. It reflects the average kinetic energy of the vibrating and colliding atoms making ...
;
*
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
In thermodynamics, the Gibbs free energy (or Gibbs energy as the recommended name; symbol is a thermodynamic potential that can be used to calculate the maximum amount of Work (thermodynamics), work, other than Work (thermodynamics)#Pressure–v ...
changes (∆''G''°) must satisfy
:,
where electrons are transferred, and the
Faraday constant
In physical chemistry, the Faraday constant (symbol , sometimes stylized as ℱ) is a physical constant defined as the quotient of the total electric charge () by the amount () of elementary charge carriers in any given sample of matter: it ...
is the
conversion factor describing
Coulomb
The coulomb (symbol: C) is the unit of electric charge in the International System of Units (SI).
It is defined to be equal to the electric charge delivered by a 1 ampere current in 1 second, with the elementary charge ''e'' as a defining c ...
s transferred per mole electrons. Those Gibbs free energy changes can be added.
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, one must have
But that equation does not hold exactly with the cited values.
__TOC__
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 potential
An electrode is an electrical conductor used to make contact with a nonmetallic part of a Electronic circuit, circuit (e.g. a semiconductor, an electrolyte, a vacuum or a gas). In electrochemical cells, electrodes are essential parts that can c ...
s in saltwater
*
Standard apparent reduction potentials in biochemistry at pH 7
*
Reactivity series#Comparison with standard electrode potentials
Notes
[Not specified in the indicated reference, but assumed due to the difference between the value −0.454 and that computed by (2×(−0.499) + (−0.508))/3 = −0.502, exactly matching the difference between the values for white (−0.063) and red (−0.111) phosphorus in equilibrium with PH3.]
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
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Electrochemistry
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