Standard electrode potential (data page)

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The standard electrode potentials are electrode potentials of half cells at equilibrium. They can be used to determine the potential of an electrochemical cell or galvanic cell, or a position of equilibrium for an electrochemical (redox) reaction, or a direction in which an electrochemical reaction can (thermodynamically) proceed.

The values of standard electrode potentials are given in the table below in volts relative to the standard hydrogen electrode and are assembled from references ^{[1] [2] [3] [4] [5] [6] [7] [8] [9]}.

The values are for the following conditions:

• the temperature of 298.15 K (25 °C),
• the effective concentration of 1 mol/L for each aqueous species,
• the partial pressure of 101.325 kPa (absolute) (1 atm, 1.01325 bar) for each gaseous reagent. This pressure is used because most literature data are still given for this value rather than for the current standard of 100 kPa,
• the activity of unity for each pure solid, pure liquid, a species in a mercury amalgam, or for water (solvent).

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

Half-reaction	E° (V)	Ref.
&	0
N  N2(g) + H+ + e− HN3(aq)	-3.09 −3.09	[6]
Li+ + e− Li(s)	-3.05 −3.05	[4]
N2(g) + 4 H2O + 2 e− 2 NH2OH(aq) + 2 OH−	-3.04 −3.04	[6]
Rb+ + e− Rb(s)	-2.98 −2.98	[4]
K+ + e− K(s)	-2.93 −2.93	[9]
Cs+ + e− Cs(s)	-2.92 −2.92	[9]
Ba2+ + 2 e− Ba(s)	-2.91 −2.91	[9]
Sr2+ + 2 e− Sr(s)	-2.89 −2.89	[9]
Ra2+ + 2 e− Ra(s)	-2.80 −2.80
Ca2+ + 2 e− Ca(s)	-2.76 −2.76
Na+ + e− Na(s)	-2.71 −2.71
Mg2+ + 2 e− Mg(s)	-2.38 −2.38
ZrO(OH)2(s) + H2O + 4 e− Zr(s) + 4OH−	-2.36 −2.36
Al(OH)4− + 3 e− Al(s) + 4 OH−	-2.33 −2.33
Al(OH)3(s) + 3 e− Al(s) + 3OH−	-2.31 −2.31
H2(g) + 2 e− 2 H−	-2.25 −2.25
Ac3+ + 3 e− Ac(s)	-2.20 −2.20
Be2+ + 2 e− Be(s)	-1.85 −1.85
U3+ + 3 e− U(s)	-1.66 −1.66	[7]
Al3+ + 3 e− Al(s)	-1.66 −1.66	[9]
Ti2+ + 2 e− Ti(s)	-1.63 −1.63	[9]
ZrO2(s) + 4 H+ + 4 e− Zr(s) + 2 H2O	-1.553 −1.553
Zr4+ + 4 e− Zr(s)	-1.45 −1.45
TiO(s) + 2 H+ + 2 e− Ti(s) + H2O	-1.31 −1.31
Ti2O3(s) + 2 H+ + 2 e− 2 TiO(s) + H2O	-1.23 −1.23
Ti3+ + 3 e− Ti(s)	-1.21 −1.21
Mn2+ + 2 e− Mn(s)	-1.18 −1.18	[9]
Te(s) + 2 e− Te2−	-1.143 −1.143	[2]
V2+ + 2 e− V(s)	-1.13 −1.13
Nb3+ + 3 e− Nb(s)	-1.099 −1.099
Sn(s) + 4 H+ + 4 e− SnH4(g)	-1.07 −1.07
SiO2(s) + 4 H+ + 4 e− Si(s) + 2 H2O	-0.91 −0.91
B(OH)3(aq) + 3 H+ + 3 e− B(s) + 3 H2O	-0.89 −0.89
TiO2+ + 2 H+ + 4 e− Ti(s) + H2O	-0.86 −0.86
Bi(s) + 3 H+ + 3 e− BiH3	-0.8 −0.8
H2 H2O + 2 e− H2(g) + 2 OH−	-0.83 −0.83
Zn2+ + 2 e− Zn(s)	-0.76 −0.76
Ta2O5(s) + 10 H+ + 10 e− 2 Ta(s) + 5 H2O	-0.75 −0.75
Cr3+ + 3 e− Cr(s)	-0.74 −0.74
Au[Au(CN)2]− + e− Au(s) +2 CN−	-0.60 −0.60
Ta3+ + 3 e− Ta(s)	-0.6 −0.6
PbO(s) + H2O + 2 e− Pb(s) + 2 OH−	-0.58 −0.58
Ti 2 TiO2(s) + 2 H+ + 2 e− Ti2O3(s) + H2O	-0.56 −0.56
Ga3+ + 3 e− Ga(s)	-0.53 −0.53
U4+ + e− U3+	-0.52 −0.52	[7]
P H3PO2(aq) + H+ + e− P(s) + 2 H2O	-0.51 −0.51
P H3PO3(aq) + 3 H+ + 3 e− P(s) + 3H2O	-0.50 −0.50
P H3PO3(aq) + 2 H+ + 2 e− H3PO2(aq) + H2O	-0.50 −0.50
Fe2+ + 2 e− Fe(s)	-0.44 −0.44
C 2CO2(g) + 2 H+ + 2 e− HOOCCOOH(aq)	-0.43 −0.43
Cr3+ + e− Cr2+	-0.42 −0.42
Cd2+ + 2 e− Cd(s)	-0.40 −0.40
GeO2(s) + 2 H+ + 2 e− GeO(s) + H2O	-0.37 −0.37
Cu2O(s) + H2O + 2 e− 2 Cu(s) + 2 OH−	-0.360 −0.360	[5]
PbSO4(s) + 2 e− Pb(s) + SO42−	-0.3588 −0.3588	[5]
PbSO4(s) + 2 e− Pb(Hg) + SO42−	-0.3505 −0.3505	[5]
Eu3+ + e− Eu2+	-0.35 −0.35	[7]
In3+ + 3 e− In(s)	-0.34 −0.34
Tl+ + e− Tl(s)	-0.34 −0.34
Ge(s) + 4 H+ + 4e− GeH4(g)	-0.29 −0.29
Co2+ + 2 e− Co(s)	-0.28 −0.28
P H3PO4(aq) + 2 H+ + 2 e− H3PO3(aq) + H2O	-0.28 −0.28
V3+ + e− V2+	-0.26 −0.26
Ni2+ + 2 e− Ni(s)	-0.25 −0.25
As(s) + 3 H+ + 3 e− AsH3(g)	-0.23 −0.23
MoO2(s) + 4 H+ + 4 e− Mo(s) + 2 H2O	-0.15 −0.15
Si(s) + 4 H+ + 4 e− SiH4(g)	-0.14 −0.14
Sn2+ + 2 e− Sn(s)	-0.13 −0.13
O2(g) + H+ + e− HO2•(aq)	-0.13 −0.13
Pb2+ + 2 e− Pb(s)	-0.13 −0.13
WO2(s) + 4 H+ + 4 e− W(s) + 2 H2O	-0.12 −0.12
C CO2(g) + 2 H+ + 2 e− HCOOH(aq)	-0.11 −0.11
Se(s) + 2 H+ + 2 e− H2Se(g)	-0.11 −0.11
C CO2(g) + 2 H+ + 2 e− CO(g) + H2O	-0.11 −0.11
SnO(s) + 2 H+ + 2 e− Sn(s) + H2O	-0.10 −0.10
SnO2(s) + 2 H+ + 2 e− SnO(s) + H2O	-0.09 −0.09
WO3(aq) + 6 H+ + 6 e− W(s) + 3 H2O	-0.09 −0.09
P(s) + 3 H+ + 3 e− PH3(g)	-0.06 −0.06
C HCOOH(aq) + 2 H+ + 2 e− HCHO(aq) + H2O	-0.03 −0.03
H 2 H+ + 2 e− H2(g)	0 ≡ 0
S4O62− + 2 e− 2 S2O32−	+0.08
Fe3O4(s) + 8 H+ + 8 e− 3 Fe(s) + 4 H2O	+0.085	[8]
N2(g) + 2 H2O + 6H+ + 6 e− 2 NH4OH(aq)	+0.092
HgO(s) + H2O + 2 e− Hg(l) + 2 OH−	+0.0977
Cu(NH3)42+ + e− Cu(NH3)2+ + 2 NH3	+0.10	[2]
Ru(NH3)63+ + e− Ru(NH3)62+	+0.10	[7]
N2H4(aq) + 4 H2O + 2 e− 2 NH4+ + 4 OH−	+0.11	[6]
Mo H2MoO4(aq) + 6 H+ + 6 e− Mo(s) + 4 H2O	+0.11
Ge4+ + 4 e− Ge(s)	+0.12
C(s) + 4 H+ + 4 e− CH4(g)	+0.13
C HCHO(aq) + 2 H+ + 2 e− CH3OH(aq)	+0.13
S(s) + 2 H+ + 2 e− H2S(g)	+0.14
Sn4+ + 2 e− Sn2+	+0.15
Cu2+ + e− Cu+	+0.159	[2]
S HSO4− + 3 H+ + 2 e− SO2(aq) + 2 H2O	+0.16
UO22+ + e− UO2+	+0.163	[7]
S SO42− + 4 H+ + 2 e− SO2(aq) + 2 H2O	+0.17
Bi3+ + 2e− Bi+	+0.2
SbO+ + 2 H+ + 3 e− Sb(s) + H2O	+0.20
As H3AsO3(aq) + 3 H+ + 3 e− As(s) + 3 H2O	+0.24
GeO(s) + 2 H+ + 2 e− Ge(s) + H2O	+0.26
UO2+ + 4 H+ + e− U4+ + 2 H2O	+0.273	[7]
Re3+ + 3 e− Re(s)	+0.300
Bi3+ + 3 e− Bi(s)	+0.32
VO2+ + 2 H+ + e− V3+ + H2O	+0.34
Cu2+ + 2 e− Cu(s)	+0.340	[2]
Fe [Fe(CN)6]3− + e− [Fe(CN)6]4−	+0.36
O2(g) + 2 H2O + 4 e− 4 OH−(aq)	+0.40
Mo H2MoO4 + 6 H+ + 3 e− Mo3+ + 2 H2O	+0.43
Bi+ + e− Bi(s)	+0.50
C CH3OH(aq) + 2 H+ + 2 e− CH4(g) + H2O	+0.50
S SO2(aq) + 4 H+ + 4 e− S(s) + 2 H2O	+0.50
Cu+ + e− Cu(s)	+0.520	[2]
C CO(g) + 2 H+ + 2 e− C(s) + H2O	+0.52
I2(s) + 2 e− 2 I−	+0.54
I3− + 2 e− 3 I−	+0.54
Au [AuI4]− + 3 e− Au(s) + 4 I−	+0.56
As H3AsO4(aq) + 2 H+ + 2 e− H3AsO3(aq) + H2O	+0.56
Au [AuI2]− + e− Au(s) + 2 I−	+0.58
MnO4− + 2 H2O + 3 e− MnO2(s) + 4 OH−	+0.59
S2O32 − + 6 H+ + 4 e− 2 S(s) + 3 H2O	+0.60
Mo H2MoO4(aq) + 2 H+ + 2 e− MoO2(s) + 2 H2O	+0.65
O2(g) + 2 H+ + 2 e− H2O2(aq)	+0.70
Tl3+ + 3 e− Tl(s)	+0.72
PtCl62− + 2 e− PtCl42− + 2 Cl−	+0.726	[7]
Se H2SeO3(aq) + 4 H+ + 4 e− Se(s) + 3 H2O	+0.74
PtCl42− + 2 e− Pt(s) + 4 Cl−	+0.758	[7]
Fe3+ + e− Fe2+	+0.77
Ag+ + e− Ag(s)	+0.7996	[5]
Hg22+ + 2 e− 2 Hg(l)	+0.80
N NO3−(aq) + 2 H+ + e− NO2(g) + H2O	+0.80
Au [AuBr4]− + 3 e− Au(s) + 4 Br−	+0.85
Hg2+ + 2 e− Hg(l)	+0.85
MnO4− + H+ + e− HMnO4−	+0.90
Hg 2 Hg2+ + 2 e− Hg22+	+0.91
Pd2+ + 2 e− Pd(s)	+0.915	[7]
Au [AuCl4]− + 3 e− Au(s) + 4 Cl−	+0.93
MnO2(s) + 4 H+ + e− Mn3+ + 2 H2O	+0.95
Au [AuBr2]− + e− Au(s) + 2 Br−	+0.96
Br2(l) + 2 e− 2 Br−	+1.07
Br2(aq) + 2 e− 2 Br−	+1.09
I IO3− + 5 H+ + 4 e− HIO(aq) + 2 H2O	+1.13
Au [AuCl2]− + e− Au(s) + 2 Cl−	+1.15
Se HSeO4− + 3 H+ + 2 e− H2SeO3(aq) + H2O	+1.15
Ag2O(s) + 2 H+ + 2 e− 2 Ag(s) + H2O	+1.17
ClO3− + 2 H+ + e− ClO2(g) + H2O	+1.18
Pt2+ + 2 e− Pt(s)	+1.188	[7]
ClO2(g) + H+ + e− HClO2(aq)	+1.19
I 2IO3− + 12 H+ + 10 e− I2(s) + 6 H2O	+1.20
ClO4− + 2 H+ + 2 e− ClO3− + H2O	+1.20
O2(g) + 4 H+ + 4 e− 2 H2O	+1.23
MnO2(s) + 4 H+ + 2 e− Mn2+ + 2H2O	+1.23
Tl3+ + 2 e− Tl+	+1.25
Cl2(g) + 2 e− 2 Cl−	+1.36
Cr2O7− − + 14 H+ + 6 e− 2 Cr3+ + 7 H2O	+1.33
CoO2(s) + 4 H+ + e− Co3+ + 2 H2O	+1.42
N 2 NH3OH+ + H+ + 2 e− N2H5+ + 2 H2O	+1.42	[6]
I 2HIO(aq) + 2 H+ + 2 e− I2(s) + 2 H2O	+1.44
Ce4+ + e− Ce3+	+1.44
BrO3− + 5 H+ + 4 e− HBrO(aq) + 2 H2O	+1.45
PbO β-PbO2(s) + 4 H+ + 2 e− Pb2+ + 2 H2O	+1.460	[2]
PbO α-PbO2(s) + 4 H+ + 2 e− Pb2+ + 2 H2O	+1.468	[2]
Br 2 BrO3− + 12 H+ + 10 e− Br2(l) + 6 H2O	+1.48
Cl 2ClO3− + 12 H+ + 10 e− Cl2(g) + 6 H2O	+1.49
MnO4− + 8 H+ + 5 e− Mn2+ + 4 H2O	+1.51
O HO2• + H+ + e− H2O2(aq)	+1.51
Au3+ + 3 e− Au(s)	+1.52
NiO2(s) + 4 H+ + 2 e− Ni2+ + 2 OH−	+1.59
Cl 2HClO(aq) + 2 H+ + 2 e− Cl2(g) + 2 H2O	+1.63
Ag2O3(s) + 6 H+ + 4 e− 2 Ag+ + 3 H2O	+1.67
Cl HClO2(aq) + 2 H+ + 2 e− HClO(aq) + H2O	+1.67
Pb4+ + 2 e− Pb2+	+1.69	[2]
MnO4− + 4 H+ + 3 e− MnO2(s) + 2 H2O	+1.70
O H2O2(aq) + 2 H+ + 2 e− 2 H2O	+1.78
AgO(s) + 2 H+ + e− Ag+ + H2O	+1.77
Co3+ + e− Co2+	+1.82
Au+ + e− Au(s)	+1.83
BrO4− + 2 H+ + 2 e− BrO3− + H2O	+1.85
Ag2+ + e− Ag+	+1.98
Cu2O3 + 2 e− 2 Cu2+ + 2 OH−	+2.0
S2O82− + 2 e− 2SO42−	+2.07
O3(g) + 2 H+ + 2 e− O2(g) + H2O	+2.075	[7]
Mn HMnO4− + 3 H+ + 2 e− MnO2(s) + 2 H2O	+2.09
F2(g) + 2 e− 2 F−	+2.87
F2(g) + 2 H+ + 2 e− 2 HF(aq)	+3.05

[edit] References

• http://www.jesuitnola.org/upload/clark/Refs/red_pot.htm
• http://hyperphysics.phy-astr.gsu.edu/Hbase/tables/electpot.html#c1

1. ^ Milazzo, G., Caroli, S., and Sharma, V. K. (1978). Tables of Standard Electrode Potentials (Wiley, Chichester).
2. ^ ^{a b c d e f g h i} Bard, A. J., Parsons, R., and Jordan, J. (1985). Standard Potentials in Aqueous Solutions (Marcel Dekker, New York).
3. ^ Bratsch, S. G. (1989). Journal of Physical Chemistry Reference Data Vol. 18, pp. 1–21.
4. ^ ^{a b c} Vanýsek, Petr (2006). "Electrochemical Series," in Handbook of Chemistry and Physics: 87^th Edition (Chemical Rubber Company).
5. ^ ^{a b c d e} Vanýsek, Petr (2007). “Electrochemical Series”, in Handbook of Chemistry and Physics: 88^th Edition (Chemical Rubber Company).
6. ^ ^{a b c d e} Greenwood, N. N.; Earnshaw, A. (1997). Chemistry of the Elements, 2nd Edition, Oxford:Butterworth-Heinemann. ISBN 0-7506-3365-4. 
7. ^ ^{a b c d e f g h i j k l} Bard, A.J., Faulkner, L.R.(2001). Electrochemical Methods. Fundamentals and Applications, 2nd edition (John Wiley and Sons Inc).
8. ^ ^{a b} Marcel Pourbaix (1966). Atlas of Electrochemical Equilibria in Aqueous Solutions (NACE International, Houston, Texas; Cebelcor, Brussels).
9. ^ ^{a b c d e f g h} Peter Atkins (1997). Physical Chemistry, 6th edition (W.H. Freeman and Company, New York).

[edit] See also

• Galvanic series
• biochemically relevant redox potentials
• Standard electrode potential