The data values of

standard electrode potential In electrochemistry, standard electrode potential E^\ominus, or E^\ominus_, is a measure of the reducing power of any element or compound. The IUPAC "Gold Book" defines it as: ''"the value of the standard emf (electromotive force) of a cell in wh ...

s (''E''°) are given in the table below, in

volt The volt (symbol: V) is the unit of electric potential, electric potential difference (voltage), and electromotive force in the International System of Units (SI). It is named after the Italian physicist Alessandro Volta (1745–1827). Defin ...

s relative to the

standard hydrogen electrode The standard hydrogen electrode (abbreviated SHE), is a redox electrode which forms the basis of the thermodynamic scale of oxidation-reduction potentials. Its absolute electrode potential is estimated to be at 25 °C, but to form a basis ...

, and are for the following conditions: * A temperature of . * An effective concentration of 1 mol/L for each aqueous species or a species in a mercury

amalgam Amalgam most commonly refers to: * Amalgam (chemistry), mercury alloy * Amalgam (dentistry), material of silver tooth fillings ** Bonded amalgam, used in dentistry Amalgam may also refer to: * Amalgam Comics, a publisher * Amalgam Digital, an in ...

(an alloy of mercury with another metal). * A

partial pressure In a mixture of gases, each constituent gas has a partial pressure which is the notional pressure of that constituent gas as if it alone occupied the entire volume of the original mixture at the same temperature. The total pressure of an ideal g ...

of 101.325 kPa (absolute) (1 atm, 1.01325

bar Bar or BAR may refer to: Food and drink * Bar (establishment), selling alcoholic beverages * Candy bar * Chocolate bar Science and technology * Bar (river morphology), a deposit of sediment * Bar (tropical cyclone), a layer of cloud * Bar ( ...

) for each gaseous reagent. This pressure is used because most literature data are still given for this value (1 atm) rather than for the current standard of 100 kPa (1 bar) presently considered in the

standard state In chemistry, the standard state of a material (pure substance, mixture or solution) is a reference point used to calculate its properties under different conditions. A superscript circle ° (degree symbol) or a Plimsoll (⦵) character is use ...

. * An activity of unity for each pure solid, pure liquid, or for water (solvent). The relation in

electrode potential In electrochemistry, electrode potential is the electromotive force of a galvanic cell built from a standard reference electrode and another electrode to be characterized. By convention, the reference electrode is the standard hydrogen electrode ...

of metals in saltwater (as

electrolyte An electrolyte is a medium containing ions that is electrically conducting through the movement of those ions, but not conducting electrons. This includes most soluble salts, acids, and bases dissolved in a polar solvent, such as water. Upon ...

) is given in the ''

galvanic series The galvanic series (or electropotential series) determines the nobility of metals and semi-metals. When two metals are submerged in an electrolyte, while also electrically connected by some external conductor, the less noble (base) will experience ...

''. * Although many of the half cells are written for multiple-electron transfers, the tabulated potentials are for a single-electron transfer. All of the reactions should be divided by the stoichiometric coefficient for the electron to get the corresponding corrected reaction equation. For example, the equation Fe + 2 Fe(''s'') (–0.44 V) means that it requires 2 × 0.44 eV = 0.88 eV of energy to be absorbed (hence the minus sign) in order to create one neutral atom of Fe(''s'') from one Fe ion and two electrons, or 0.44 eV per electron, which is 0.44 J/C of electrons, which is 0.44 V. * After dividing by the number of electrons, the standard potential ''E''° is related to the

standard Gibbs free energy of formation The standard Gibbs free energy of formation (''G''f°) of a compound is the change of Gibbs free energy that accompanies the formation of 1 mole of a substance in its standard state from its constituent elements in their standard states (the most ...

''ΔG_f°'' by:

E = \frac

where ''F'' is the

Faraday constant In physical chemistry, the Faraday constant, denoted by the symbol and sometimes stylized as ℱ, is the electric charge per mole of elementary charges. It is named after the English scientist Michael Faraday. Since the 2019 redefinition of ...

. For example, in the equation Fe + 2 Fe(''s'') (–0.44 V), the Gibbs energy required to create one neutral atom of Fe(''s'') from one Fe ion and two electrons is 2 × 0.44 eV = 0.88 eV, or 84 895 J/mol of electrons, which is just the Gibbs energy of formation of an Fe ion, since the energies of formation of and Fe(''s'') are both zero. :The

Nernst equation 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 tempe ...

will then give potentials at concentrations, pressures, and temperatures other than standard. * Note that the table may lack consistency due to data from different sources. For example: : :Calculating the potential using

Gibbs free energy In thermodynamics, the Gibbs free energy (or Gibbs energy; symbol G) is a thermodynamic potential that can be used to calculate the maximum amount of work that may be performed by a thermodynamically closed system at constant temperature an ...

( = 2 – ) gives the potential for as 0.154 V, not the experimental value of 0.159 V. : __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.

Notes

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 {{DEFAULTSORT:Standard Electrode Potentials Electrochemistry Electrochemical potentials Chemistry-related lists

Table of standard electrode potentials

See also

Notes

References

External links