Standard electrode potential (data page)

The values of standard electrode potentials are given in the table below in volts relative to the standard hydrogen electrode and are for the following conditions:

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

Half-reaction (V)[note 1] Ref.
& -9
Zz 9
3⁄​2N2(g) + H+ + e HN3(aq)  −3.09 [1]
Li+ + e Li(s)  −3.0401 [2]
N2(g) + 4H2O + 2e 2NH2OH(aq) + 2OH  −3.04 [1]
Cs+ + e Cs(s)  −3.026 [2]
Rb+ + e Rb(s)  −2.98 [2]
K+ + e K(s)  −2.931 [2]
Ba2+ + 2e Ba(s)  −2.912 [2]
La(OH)3(s) + 3e La(s) + 3OH  −2.90 [2]
Sr2+ + 2e Sr(s)  −2.899 [2]
Ca2+ + 2e Ca(s)  −2.868 [2]
Eu2+ + 2e Eu(s)  −2.812 [2]
Ra2+ + 2e Ra(s)  −2.8 [2]
Na+ + e Na(s)  −2.71 [2][3]
La3+ + 3e La(s)  −2.379 [2]
Y3+ + 3e Y(s)  −2.372 [2]
Mg2+ + 2e Mg(s)  −2.372 [2]
ZrO(OH)2(s) + H2O + 4e Zr(s) + 4OH  −2.36 [2]
Al(OH)4 + 3e Al(s) + 4OH  −2.33
Al(OH)3(s) + 3e Al(s) + 3OH  −2.31
H2(g) + 2e 2H  −2.25
Ac3+ + 3e Ac(s)  −2.20
Be2+ + 2e Be(s)  −1.85
U3+ + 3e U(s)  −1.66 [4]
Al3+ + 3e Al(s)  −1.66 [3]
Ti2+ + 2e Ti(s)  −1.63 [3]
ZrO2(s) + 4H+ + 4e Zr(s) + 2H2O  −1.553 [2]
Zr4+ + 4e Zr(s)  −1.45 [2]
Ti3+ + 3e Ti(s)  −1.37 [5]
TiO(s) + 2H+ + 2e Ti(s) + H2O  −1.31
Ti2O3(s) + 2H+ + 2e 2TiO(s) + H2O  −1.23
Zn(OH)42− + 2e Zn(s) + 4OH  −1.199 [2]
Mn2+ + 2e Mn(s)  −1.185 [2]
Fe(CN)64− + 6H+ + 2 e Fe(s) + 4HCN(aq)  −1.16 [6]
Te(s) + 2e Te2−  −1.143 [7]
V2+ + 2e V(s)  −1.13 [7]
Nb3+ + 3e Nb(s)  −1.099
Sn(s) + 4H+ + 4e SnH4(g)  −1.07
SiO2(s) + 4H+ + 4e Si(s) + 2H2O  −0.91
B(OH)3(aq) + 3H+ + 3e B(s) + 3H2O  −0.89
Fe(OH)2(s) + 2e Fe(s) + 2OH  −0.89 [6]
Fe2O3(s) + 3H2O + 2e 2Fe(OH)2(s) + 2OH  −0.86 [6]
TiO2+ + 2H+ + 4e Ti(s) + H2O  −0.86
2H2O + 2e H2(g) + 2OH  −0.8277 [2]
Bi(s) + 3H+ + 3e BiH3  −0.8 [2]
Zn2+ + 2e Zn(Hg)  −0.7628 [2]
Zn2+ + 2e Zn(s)  −0.7618 [2]
Ta2O5(s) + 10H+ + 10e 2Ta(s) + 5H2O  −0.75
Cr3+ + 3e Cr(s)  −0.74
[Au(CN)2] + e Au(s) + 2CN  −0.60
Ta3+ + 3e Ta(s)  −0.6
PbO(s) + H2O + 2e Pb(s) + 2OH  −0.58
2TiO2(s) + 2H+ + 2e Ti2O3(s) + H2O  −0.56
Ga3+ + 3e Ga(s)  −0.53
U4+ + e U3+  −0.52 [4]
H3PO2(aq) + H+ + e P(white)[note 2] + 2H2O  −0.508 [2]
H3PO3(aq) + 2H+ + 2e H3PO2(aq) + H2O  −0.499 [2]
H3PO3(aq) + 3H+ + 3e P(red)[note 2] + 3H2O  −0.454 [2]
Fe2+ + 2e Fe(s)  −0.44 [3]
2CO2(g) + 2H+ + 2e HOOCCOOH(aq)  −0.43
Cr3+ + e Cr2+  −0.42
Cd2+ + 2e Cd(s)  −0.40 [3]
GeO2(s) + 2H+ + 2e GeO(s) + H2O  −0.37
Cu2O(s) + H2O + 2e 2Cu(s) + 2OH  −0.360 [2]
PbSO4(s) + 2e Pb(s) + SO42−  −0.3588 [2]
PbSO4(s) + 2e Pb(Hg) + SO42−  −0.3505 [2]
Eu3+ + e Eu2+  −0.35 [4]
In3+ + 3e In(s)  −0.34 [7]
Tl+ + e Tl(s)  −0.34 [7]
Ge(s) + 4H+ + 4e GeH4(g)  −0.29
Co2+ + 2e Co(s)  −0.28 [2]
H3PO4(aq) + 2H+ + 2e H3PO3(aq) + H2O  −0.276 [2]
V3+ + e V2+  −0.26 [3]
Ni2+ + 2e Ni(s)  −0.25
As(s) + 3H+ + 3e AsH3(g)  −0.23 [7]
AgI(s) + e Ag(s) + I  −0.15224 [2]
MoO2(s) + 4H+ + 4e Mo(s) + 2H2O  −0.15
Si(s) + 4H+ + 4e SiH4(g)  −0.14
Sn2+ + 2e Sn(s)  −0.13
O2(g) + H+ + e HO2•(aq)  −0.13
Pb2+ + 2e Pb(s)  −0.13 [3]
WO2(s) + 4H+ + 4e W(s) + 2H2O  −0.12
P(red) + 3H+ + 3e PH3(g)  −0.111 [2]
CO2(g) + 2H+ + 2e HCOOH(aq)  −0.11
Se(s) + 2H+ + 2e H2Se(g)  −0.11
CO2(g) + 2H+ + 2e CO(g) + H2O  −0.11
SnO(s) + 2H+ + 2e Sn(s) + H2O  −0.10
SnO2(s) + 2H+ + 2e SnO(s) + H2O  −0.09
WO3(aq) + 6H+ + 6e W(s) + 3H2O  −0.09 [7]
P(white) + 3H+ + 3e PH3(g)  −0.063 [2]
Fe3+ + 3e Fe(s)  −0.04 [6]
HCOOH(aq) + 2H+ + 2e HCHO(aq) + H2O  −0.03
2H+ + 2e H2(g)    0.0000 ≡ 0
AgBr(s) + e Ag(s) + Br  +0.07133 [2]
S4O62− + 2e 2S2O32−  +0.08
Fe3O4(s) + 8H+ + 8e 3Fe(s) + 4H2O  +0.085 [8]
N2(g) + 2H2O + 6H+ + 6e 2NH4OH(aq)  +0.092
HgO(s) + H2O + 2e Hg(l) + 2OH  +0.0977
Cu(NH3)42+ + e Cu(NH3)2+ + 2NH3  +0.10 [7]
Ru(NH3)63+ + e Ru(NH3)62+  +0.10 [4]
N2H4(aq) + 4H2O + 2e 2NH4+ + 4OH  +0.11 [1]
H2MoO4(aq) + 6H+ + 6e Mo(s) + 4H2O  +0.11
Ge4+ + 4e Ge(s)  +0.12
C(s) + 4H+ + 4e CH4(g)  +0.13 [7]
HCHO(aq) + 2H+ + 2e CH3OH(aq)  +0.13
S(s) + 2H+ + 2e H2S(g)  +0.14
Sn4+ + 2e Sn2+  +0.15
Cu2+ + e Cu+  +0.159 [7]
HSO4 + 3H+ + 2e SO2(aq) + 2H2O  +0.16
UO22+ + e UO2+  +0.163 [4]
SO42− + 4H+ + 2e SO2(aq) + 2H2O  +0.17
TiO2+ + 2H+ + e Ti3+ + H2O  +0.19
SbO+ + 2H+ + 3e Sb(s) + H2O  +0.20
AgCl(s) + e Ag(s) + Cl  +0.22233 [2]
H3AsO3(aq) + 3H+ + 3e As(s) + 3H2O  +0.24
GeO(s) + 2H+ + 2e Ge(s) + H2O  +0.26
UO2+ + 4H+ + e U4+ + 2H2O  +0.273 [4]
Re3+ + 3e Re(s)  +0.300
Bi3+ + 3e Bi(s)  +0.308 [2]
VO2+ + 2H+ + e V3+ + H2O  +0.34
Cu2+ + 2e Cu(s)  +0.340 [7]
[Fe(CN)6]3− + e [Fe(CN)6]4−  +0.36
O2(g) + 2H2O + 4e 4OH(aq)  +0.40 [3]
H2MoO4 + 6H+ + 3e Mo3+ + 2H2O  +0.43
CH3OH(aq) + 2H+ + 2e CH4(g) + H2O  +0.50
SO2(aq) + 4H+ + 4e S(s) + 2H2O  +0.50
Cu+ + e Cu(s)  +0.520 [7]
CO(g) + 2H+ + 2e C(s) + H2O  +0.52
I3 + 2e 3I  +0.53 [3]
I2(s) + 2e 2I  +0.54 [3]
[AuI4] + 3e Au(s) + 4I  +0.56
H3AsO4(aq) + 2H+ + 2e H3AsO3(aq) + H2O  +0.56
[AuI2] + e Au(s) + 2I  +0.58
MnO4 + 2H2O + 3e MnO2(s) + 4OH  +0.59
S2O32 + 6H+ + 4e 2S(s) + 3H2O  +0.60
Fc+ + e Fc(s)  +0.641 [9]
H2MoO4(aq) + 2H+ + 2e MoO2(s) + 2H2O  +0.65
+ 2H+ + 2e  +0.6992 [2]
O2(g) + 2H+ + 2e H2O2(aq)  +0.70
Tl3+ + 3e Tl(s)  +0.72
PtCl62− + 2e PtCl42− + 2Cl  +0.726 [4]
H2SeO3(aq) + 4H+ + 4e Se(s) + 3H2O  +0.74
PtCl42− + 2e Pt(s) + 4Cl  +0.758 [4]
Fe3+ + e Fe2+  +0.77
Ag+ + e Ag(s)  +0.7996 [2]
Hg22+ + 2e 2Hg(l)  +0.80
NO3(aq) + 2H+ + e NO2(g) + H2O  +0.80
FeO42− + 5H2O + 6e Fe2O3(s) + 10 OH  +0.81 [6]
[AuBr4] + 3e Au(s) + 4Br  +0.85
Hg2+ + 2e Hg(l)  +0.85
MnO4 + H+ + e HMnO4  +0.90
2Hg2+ + 2e Hg22+  +0.91 [7]
Pd2+ + 2e Pd(s)  +0.915 [4]
[AuCl4] + 3e Au(s) + 4Cl  +0.93
MnO2(s) + 4H+ + e Mn3+ + 2H2O  +0.95
[AuBr2] + e Au(s) + 2Br  +0.96
[HXeO6]3− + 2H2O + 2e + [HXeO4] + 4OH  +0.99 [10]
H6TeO6(aq) + 2H+ + 2e TeO2(s) + 4H2O  +1.02 [11]
Br2(l) + 2e 2Br  +1.066 [2]
Br2(aq) + 2e 2Br  +1.0873 [2]
IO3 + 5H+ + 4e HIO(aq) + 2H2O  +1.13
[AuCl2] + e Au(s) + 2Cl  +1.15
HSeO4 + 3H+ + 2e H2SeO3(aq) + H2O  +1.15
Ag2O(s) + 2H+ + 2e 2Ag(s) + H2O  +1.17
ClO3 + 2H+ + e ClO2(g) + H2O  +1.18
[HXeO6]3− + 5H2O + 8 e Xe(g) + 11OH  +1.18 [10]
Pt2+ + 2e Pt(s)  +1.188 [4]
ClO2(g) + H+ + e HClO2(aq)  +1.19
2IO3 + 12H+ + 10e I2(s) + 6H2O  +1.20
ClO4 + 2H+ + 2e ClO3 + H2O  +1.20
O2(g) + 4H+ + 4e 2H2O  +1.229 [3]
MnO2(s) + 4H+ + 2e Mn2+ + 2H2O  +1.23
[HXeO4] + 3H2O + 6 e Xe(g) + 7OH  +1.24 [10]
Tl3+ + 2e Tl+  +1.25
Cr2O72− + 14H+ + 6e 2Cr3+ + 7H2O  +1.33
Cl2(g) + 2e 2Cl  +1.36 [3]
CoO2(s) + 4H+ + e Co3+ + 2H2O  +1.42
2NH3OH+ + H+ + 2e N2H5+ + 2H2O  +1.42 [1]
2HIO(aq) + 2H+ + 2e I2(s) + 2H2O  +1.44
Ce4+ + e Ce3+  +1.44
BrO3 + 5H+ + 4e HBrO(aq) + 2H2O  +1.45
β-PbO2(s) + 4H+ + 2e Pb2+ + 2H2O  +1.460 [7]
α-PbO2(s) + 4H+ + 2e Pb2+ + 2H2O  +1.468 [7]
2BrO3 + 12H+ + 10e Br2(l) + 6H2O  +1.48
2ClO3 + 12H+ + 10e Cl2(g) + 6H2O  +1.49
MnO4 + 8H+ + 5e Mn2+ + 4H2O  +1.51
HO2 + H+ + e H2O2(aq)  +1.51
Au3+ + 3e Au(s)  +1.52
NiO2(s) + 4H+ + 2e Ni2+ + 2OH  +1.59
2HClO(aq) + 2H+ + 2e Cl2(g) + 2H2O  +1.63
Ag2O3(s) + 6H+ + 4e 2Ag+ + 3H2O  +1.67
HClO2(aq) + 2H+ + 2e HClO(aq) + H2O  +1.67
Pb4+ + 2e Pb2+  +1.69 [7]
MnO4 + 4H+ + 3e MnO2(s) + 2H2O  +1.70
AgO(s) + 2H+ + e Ag+ + H2O  +1.77
H2O2(aq) + 2H+ + 2e 2H2O  +1.78
Co3+ + e Co2+  +1.82
Au+ + e Au(s)  +1.83 [7]
BrO4 + 2H+ + 2e BrO3 + H2O  +1.85
Ag2+ + e Ag+  +1.98 [7]
S2O82− + 2e 2SO42−  +2.010 [2]
O3(g) + 2H+ + 2e O2(g) + H2O  +2.075 [4]
HMnO4 + 3H+ + 2e MnO2(s) + 2H2O  +2.09
XeO3(aq) + 6H+ + 6 e Xe(g) + 3H2O  +2.12 [10]
H4XeO6(aq) + 8H+ + 8 e Xe(g) + 6 H2O  +2.18 [10]
FeO42− + 3e + 8H+ Fe3+ + 4H2O  +2.20 [12]
XeF2(aq) + 2H+ + 2e Xe(g) + 2HF(aq)  +2.32 [10]
H4XeO6(aq) + 2H+ + 2e XeO3(aq) + H2O  +2.42 [10]
F2(g) + 2e 2F  +2.87 [7][3]
F2(g) + 2H+ + 2e 2HF(aq)  +3.05 [7]
  1. ^ Clicking on this column to re-sort by potential didn’t work in the Safari web browser in v. 4.0.3 or earlier (but works in v. 4.0.5). In this case just reload the page to restore the original order.
  2. ^ a b 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.

In oxidative phosphorylation

Oxidative phosphorylation is the means by which organism generate energy, and is driven by differences in electrode potential between intermediaries in a chain of reactions.

The following values are calculated for pH 7, which is more biologically realistic, but makes the values incompatible with the values in the table above with standard criteria.

Respiratory enzymes and substrates in eukaryotes.
Respiratory enzyme Redox pair  Midpoint potential 

(Volts)

 NADH dehydrogenase NAD+ / NADH −0.32[13]
 Succinate dehydrogenase FMN or FAD / FMNH2 or FADH2 −0.20[13]
 Cytochrome bc1 complex Coenzyme Q10ox / Coenzyme Q10red +0.06[13]
 Cytochrome bc1 complex Cytochrome box / Cytochrome bred +0.12[13]
 Complex IV Cytochrome cox / Cytochrome cred +0.22[13]
 Complex IV Cytochrome aox / Cytochrome ared +0.29[13]
 Complex IV O2 / HO +0.82[13]

References

  1. ^ a b c d Greenwood, Norman N.; Earnshaw, Alan (1997). Chemistry of the Elements (2nd ed.). Oxford: Butterworth-Heinemann. ISBN 0080379419. 
  2. ^ a b c d e f g h i j k l m n o p q r s t u v w x y z aa ab ac ad ae af ag ah ai aj ak al am an ao ap Vanýsek, Petr (2007). “Electrochemical Series”, in Handbook of Chemistry and Physics: 88th Edition (Chemical Rubber Company).
  3. ^ a b c d e f g h i j k l m Peter Atkins (1997). Physical Chemistry, 6th edition (W.H. Freeman and Company, New York).
  4. ^ a b c d e f g h i j k Bard, A.J., Faulkner, L.R.(2001). Electrochemical Methods. Fundamentals and Applications, 2nd edition (John Wiley and Sons Inc).
  5. ^ Gordon Aylward & Tristan Findlay (2008). "SI Chemical Data", 6th edition (John Wiley & Sons, Australia), ISBN 9780470816387.
  6. ^ a b c d e WebElements Periodic Table of the Elements | Iron | compounds information
  7. ^ a b c d e f g h i j k l m n o p q r s Bard, A. J., Parsons, R., and Jordan, J. (1985). Standard Potentials in Aqueous Solutions (Marcel Dekker, New York).
  8. ^ Marcel Pourbaix (1966). Atlas of Electrochemical Equilibria in Aqueous Solutions (NACE International, Houston, Texas; Cebelcor, Brussels).
  9. ^ Connelly, Neil G.; Geiger, William E. (1 January 1996). "Chemical Redox Agents for Organometallic Chemistry". Chemical Reviews 96 (2): 877–910. doi:10.1021/cr940053x. PMID 11848774. 
  10. ^ a b c d e f g WebElements Periodic Table of the Elements | Xenon | compounds information
  11. ^ Cotton, F. Albert; Wilkinson, Geoffrey; Murillo, Carlos A.; Bochmann, Manfred (1999), Advanced Inorganic Chemistry (6th ed.), New York: Wiley-Interscience, ISBN 0-471-19957-5 
  12. ^ Redox Reactions, Western Oregon University website
  13. ^ a b c d e f g Medical CHEMISTRY Compendium. By Anders Overgaard Pedersen and Henning Nielsen. Aarhus University. 2008

See also