Standard electrode potential (data page)

Home Page | Standard electrode potential (data page)

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

  • Temperature 298.15 K (25.00 °C; 77.00 °F);
  • Effective concentration (activity) 1 (dimensionless) for each aqueous or amalgamated (mercury-alloyed) species;
  • Unit activity for each solvent and pure solid or liquid species; and
  • Absolute partial pressure 101.325 kPa (1.00000 atm; 1.01325 bar) 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

∆G° = –zFE°,

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

Fe2+ + 2 e− ⇌ Fe(s) (−0.44 V),

the energy to form one neutral atom of Fe(s) from one Fe2+ ion and two electrons is 2 × 0.44 eV = 0.88 eV, or 84 907 J/(mol  e−). That value is also the standard formation energy (∆Gf°) for an Fe2+ ion, since  e− 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.

Element Half-reaction E°
(volt) 		Electrons
transferred 		Reference
Oxidant ⇌ Reductant
Sr Sr+
 +  e− 		⇌ Sr(s) −4.101 1
Ca Ca+
 +  e− 		⇌ Ca(s) −3.8 1
Th Th4+
 +  e− 		⇌ Th3+
 		−3.6 1
Pr Pr3+
 +  e− 		⇌ Pr2+
 		−3.1 1 Estimated
N 3N
2(g) + 2 H+ + 2 e− 		⇌ 2HN
3(aq) 		−3.09 2
Li Li+
 +  e− 		⇌ Li(s) −3.0401 1 : 153 
N N
2(g) + 4H2O + 2 e− 		⇌ 2NH
2OH(aq) + 2 OH− 		−3.04 2
Cs Cs+
 +  e− 		⇌ Cs(s) −3.026 1
Ca Ca(OH)
2 + 2 e− 		⇌ Ca(s) + 2 OH− −3.02 2
Er Er3+
 +  e− 		⇌ Er2+
 		−3 1
Ba Ba(OH)
2 + 2 e− 		⇌ Ba(s) + 2 OH− −2.99 2
Rb Rb+
 +  e− 		⇌ Rb(s) −2.98 1
K K+
 +  e− 		⇌ K(s) −2.931 1
Ba Ba2+
 + 2 e− 		⇌ Ba(s) −2.912 2
La La(OH)
3(s) + 3 e− 		⇌ La(s) + 3 OH− −2.9 3
Fr Fr+
 +  e− 		⇌ Fr(s) −2.9 1
Sr Sr2+
 + 2 e− 		⇌ Sr(s) −2.899 2
Sr Sr(OH)
2 + 2 e− 		⇌ Sr(s) + 2 OH− −2.88 2
Ca Ca2+
 + 2 e− 		⇌ Ca(s) −2.868 2 : 153 
Li Li+
 + C
6(s) +  e− 		⇌ LiC
6(s) 		−2.84 1
Eu Eu2+
 + 2 e− 		⇌ Eu(s) −2.812 2
Ra Ra2+
 + 2 e− 		⇌ Ra(s) −2.8 2
Ho Ho3+
 +  e− 		⇌ Ho2+ −2.8 1
Bk Bk3+
 +  e− 		⇌ Bk2+
 		−2.8 1
Yb Yb2+
 + 2 e− 		⇌ Yb(s) −2.76 2
Na Na+
 +  e− 		⇌ Na(s) −2.71 1
Mg Mg+
 +  e− 		⇌ Mg(s) −2.7 1
Nd Nd3+
 +  e− 		⇌ Nd2+
 		−2.7 1
Mg Mg(OH)
2 + 2 e− 		⇌ Mg(s) + 2 OH− −2.69 2
Sm Sm2+
 + 2 e− 		⇌ Sm(s) −2.68 2
Be Be
2O2−
3 + 3H2O + 4 e− 		⇌ 2Be(s) + 6 OH− −2.63 4
Pm Pm3+
 +  e− 		⇌ Pm2+
 		−2.6 1
Dy Dy3+
 +  e− 		⇌ Dy2+
 		−2.6 1
No No2+
 + 2 e− 		⇌ No −2.5 2
Hf HfO(OH)
2 + H2O + 4 e− 		⇌ Hf(s) + 4 OH− −2.5 4
Th Th(OH)
4 + 4 e− 		⇌ Th(s) + 4 OH− −2.48 4
Md Md2+
 + 2 e− 		⇌ Md −2.4 2
Tm Tm2+
 + 2 e− 		⇌ Tm(s) −2.4 2
La La3+
 + 3 e− 		⇌ La(s) −2.379 3
Y Y3+
 + 3 e− 		⇌ Y(s) −2.372 3
Mg Mg2+
 + 2 e− 		⇌ Mg(s) −2.372 2
Sc ScF3(aq) + 3 H+ + 3 e− ⇌ Sc(s) + 3HF(aq) −2.37 3 : 792 
Zr ZrO(OH)
2(s) + H2O + 4 e− 		⇌ Zr(s) + 4 OH− −2.36 4
Pr Pr3+
 + 3 e− 		⇌ Pr(s) −2.353 3
Ce Ce3+
 + 3 e− 		⇌ Ce(s) −2.336 3
Er Er3+
 + 3 e− 		⇌ Er(s) −2.331 3
Ho Ho3+
 + 3 e− 		⇌ Ho(s) −2.33 3
Al H
2AlO−
3 + H2O + 3 e− 		⇌ Al(s) + 4 OH− −2.33 3
Nd Nd3+
 + 3 e− 		⇌ Nd(s) −2.323 3
Tm Tm3+
 + 3 e− 		⇌ Tm(s) −2.319 3
Al Al(OH)
3(s) + 3 e− 		⇌ Al(s) + 3 OH− −2.31 3
Sm Sm3+
 + 3 e− 		⇌ Sm(s) −2.304 3
Fm Fm2+ + 2 e− ⇌ Fm −2.3 2
Am Am3+
 +  e− 		⇌ Am2+
 		−2.3 1
Dy Dy3+
 + 3 e− 		⇌ Dy(s) −2.295 3
Lu Lu3+
 + 3 e− 		⇌ Lu(s) −2.28 3
Sc ScF+
2 + 2 H+ + 3 e−		 ⇌ Sc(s) + 2HF(l) −2.28 3 : 792 
Tb Tb3+
 + 3 e− 		⇌ Tb(s) −2.28 3
Gd Gd3+
 + 3 e− 		⇌ Gd(s) −2.279 3
H H
2(g) + 2 e− 		⇌ 2H−
 		−2.23 2
Es Es2+
 + 2 e− 		⇌ Es(s) −2.23 2
Pm Pm2+
 + 2 e− 		⇌ Pm(s) −2.2 2
Tm Tm3+
 +  e− 		⇌ Tm2+ −2.2 1
Dy Dy2+
 + 2 e− 		⇌ Dy(s) −2.2 2
Ac Ac3+
 + 3 e− 		⇌ Ac(s) −2.2 3
Yb Yb3+
 + 3 e− 		⇌ Yb(s) −2.19 3
Cf Cf2+
 + 2 e− 		⇌ Cf(s) −2.12 2
Nd Nd2+
 + 2 e− 		⇌ Nd(s) −2.1 2
Ho Ho2+
 + 2 e− 		⇌ Ho(s) −2.1 2
Sc Sc3+
 + 3 e− 		⇌ Sc(s) −2.077 3
Al AlF3−
6 + 3 e− 		⇌ Al(s) + 6F−
 		−2.069 3
Cm Cm3+
 + 3 e− 		⇌ Cm(s) −2.04 3
Pu Pu3+
 + 3 e− 		⇌ Pu(s) −2.031 3
Pr Pr2+
 + 2 e− 		⇌ Pr(s) −2 2
Er Er2+
 + 2 e− 		⇌ Er(s) −2 2
Eu Eu3+
 + 3 e− 		⇌ Eu(s) −1.991 3
Lr Lr3+
 + 3 e− 		⇌ Lr −1.96 3
Cf Cf3+
 + 3 e− 		⇌ Cf(s) −1.94 3
Es Es3+
 + 3 e− 		⇌ Es(s) −1.91 3
Pa Pa4+
 +  e− 		⇌ Pa3+
 		−1.9 1
Am Am2+
 + 2 e− 		⇌ Am(s) −1.9 2
Th Th4+
 + 4 e− 		⇌ Th(s) −1.899 4
Fm Fm3+
 + 3 e− 		⇌ Fm −1.89 3
N N2(g) + 2H2O(l) + 4 H+ + 2 e− ⇌ 2NH3OH+ −1.87 2 : 789 
Np Np3+
 + 3 e− 		⇌ Np(s) −1.856 3
Be Be2+
 + 2 e− 		⇌ Be(s) −1.847 2
P H
2PO−
2 +  e− 		⇌ P(s) + 2 OH− −1.82 1
U U3+
 + 3 e− 		⇌ U(s) −1.798 3
Sr Sr2+
 + 2 e− 		⇌ Sr(Hg) −1.793 2
B H
2BO−
3 + H2O + 3 e− 		⇌ B(s) + 4 OH− −1.79 3
Th ThO
2 + 4 H+ + 4 e− 		⇌ Th(s) + 2H2O −1.789 4
Hf HfO2+
 + 2 H+ + 4 e− 		⇌ Hf(s) + H2O −1.724 4
P HPO2−
3 + 2H2O + 3 e− 		⇌ P(s) + 5 OH− −1.71 3
Si SiO2−
3 + 3H2O + 4 e− 		⇌ Si(s) + 6 OH− −1.697 4
Al Al3+
 + 3 e− 		⇌ Al(s) −1.662 3
Ti Ti2+
 + 2 e− 		⇌ Ti(s) −1.63 2
Zr ZrO
2(s) + 4 H+ + 4 e− 		⇌ Zr(s) + 2H2O −1.553 4
Zr Zr4+
 + 4 e− 		⇌ Zr(s) −1.45 4
Ti Ti3+
 + 3 e− 		⇌ Ti(s) −1.37 3
Ti TiO(s) + 2 H+ + 2 e− ⇌ Ti(s) + H2O −1.31 2 : 792 
B B(OH)−
4 + 4H2O(l) + 8 e−		 ⇌ BH−
4 + 8 OH−		 −1.24 8 : 788 
Ti Ti
2O
3(s) + 2 H+ + 2 e− 		⇌ 2TiO(s) + H2O −1.23 2 : 792 
Ga GaO(OH)−
2 + H2O(l) + 3 e−		 ⇌ Ga(s) + 3 OH− −1.22 3 : 788 
Zn Zn(OH)2−
4 + 2 e− 		⇌ Zn(s) + 4 OH− −1.199 2
Mn Mn2+
 + 2 e− 		⇌ Mn(s) −1.185 2
Fe Fe(CN)4−
6 + 6 H+ + 2 e− 		⇌ Fe(s) + 6HCN(aq) −1.16 2
C C(s) + 3H2O(l) + 2 e− ⇌ CH3OH(l) + 2 OH− −1.148 2 : 788 
Cr Cr(CN)3−
6 +  e−		 ⇌ Cr(CN)4−
6		 −1.143 1 : 793 
Te Te(s) + 2 e− ⇌ Te2−
 		−1.143 2
V V2+
 + 2 e− 		⇌ V(s) −1.13 2
Nb Nb3+
 + 3 e− 		⇌ Nb(s) −1.099 3
Sn Sn(s) + 4 H+ + 4 e− ⇌ SnH
4(g) 		−1.07 4
Po Po(s) + 2 e− ⇌ Po2−
 		−1.021 2
Cr [Cr(edta)(H2O)]− +  e− ⇌ [Cr(edta)(H2O)]2− −0.99 1 : 793 
P 2H3PO4(aq) + 2 H+ + 2 e− ⇌ (H2PO3)2(aq) + H2O(l) −0.933 2 : 789 
C CO2−
3 + 3 H+ + 2 e−		 ⇌ HCO−
2 + H2O(l)		 −0.93 2 : 788 
Ti TiO2+
 + 2 H+ + 4 e− 		⇌ Ti(s) + H2O −0.93 4
Si SiO
2(quartz) + 4 H+ + 4 e− 		⇌ Si(s) + 2H2O −0.909 4 : 788 
Cr Cr2+
 + 2 e−		 ⇌ Cr(s) −0.9 2 : 793 
B B(OH)
3(aq) + 3 H+ + 3 e− 		⇌ B(s) + 3H2O −0.89 3 : 788 
Fe Fe(OH)
2(s) + 2 e− 		⇌ Fe(s) + 2 OH− −0.89 2
Fe Fe
2O
3(s) + 3H2O + 2 e− 		⇌ 2Fe(OH)
2(s) + 2 OH− 		−0.86 2
H 2H2O + 2 e− ⇌ H
2(g) + 2 OH− 		−0.8277 2
Bi Bi(s) + 3 H+ + 3 e− ⇌ BiH
3 		−0.8 3
Zn Zn2+
 + 2 e− 		⇌ Zn(Hg) −0.7628 2
Zn Zn2+
 + 2 e− 		⇌ Zn(s) −0.7618 2
Ta Ta
2O
5(s) + 10 H+ + 10 e− 		⇌ 2Ta(s) + 5H2O −0.75 10
Cr Cr3+
 + 3 e− 		⇌ Cr(s) −0.74 3
Te 2Te(s) + 2 e− ⇌ Te2−
2		 −0.74 2 : 790 
Ni Ni(OH)
2(s) + 2 e− 		⇌ Ni(s) + 2 OH− −0.72 2
Nb Nb2O5(s) + 10 H+ + 10 e− ⇌ 2Nb(s) + 5H2O(l) −0.7 10 : 793 
Ag Ag
2S(s) + 2 e− 		⇌ 2Ag(s) + S2−
(aq) 		−0.69 2
Te Te2−
2 + 4 H+ + 2 e−		 ⇌ 2H2Te(g) −0.64 2 : 790 
Sb Sb(OH)−
4 + 3 e−		 ⇌ Sb(s) + 4 OH− −0.639 3 : 789 
Au [Au(CN)
2]−
 +  e− 		⇌ Au(s) + 2CN−
 		−0.6 1
Ta Ta3+
 + 3 e− 		⇌ Ta(s) −0.6 3
Pb PbO(s) + H2O + 2 e− ⇌ Pb(s) + 2 OH− −0.580 2
Ti 2TiO
2(s) + 2 H+ + 2 e− 		⇌ Ti
2O
3(s) + H2O 		−0.56 2 : 792 
Ga Ga3+
 + 3 e− 		⇌ Ga(s) −0.549 3
U U4+
 +  e− 		⇌ U3+
 		−0.52 1
P H
3PO
2(aq) +  H+ +  e− 		⇌ P(white) + 2H2O −0.508 1
P H
3PO
3(aq) + 2 H+ + 2 e− 		⇌ H
3PO
2(aq) + H2O 		−0.499 2
Ni NiO
2(s) + 2H2O + 2 e− 		⇌ Ni(OH)
2(s) + 2 OH− 		−0.49 2
Sb Sb(OH)−
6 + 2 e−		 ⇌ Sb(OH)−
4 + 2 OH−		 −0.465 2 : 789 
P H
3PO
3(aq) + 3 H+ + 3 e− 		⇌ P(red) + 3H2O −0.454 3
Bi Bi2O3(s) + 3H2O(l) + 6 e− ⇌ Bi(s) + 6 OH− −0.452 6 : 789 
Ta TaF2−
7 + 7 H+ + 5 e−		 ⇌ Ta(s) + 7HF(l) −0.45 5 : 793 
In In3+
 + 2 e−		 ⇌ In+ −0.444 2 : 788 
Cu Cu(CN)−
2 +  e− 		⇌ Cu(s) + 2CN−
 		−0.44 1
Fe Fe2+
 + 2 e− 		⇌ Fe(s) −0.44 2
C 2CO
2(g) + 2 H+ + 2 e− 		⇌ HOOCCOOH(aq) −0.43 2
Cr Cr3+
 +  e− 		⇌ Cr2+
 		−0.407 1
Cd Cd2+
 + 2 e− 		⇌ Cd(s) −0.4 2
Ti Ti3+
 +  e−		 ⇌ Ti2+
 −0.37 1 : 792 
Cu Cu
2O(s) + H2O + 2 e− 		⇌ 2Cu(s) + 2 OH− −0.36 2
Pb PbSO
4(s) + 2 e− 		⇌ Pb(s) + SO2−
4 		−0.3588 2
Pb PbSO
4(s) + 2 e− 		⇌ Pb(Hg) + SO2−
4 		−0.3505 2
Eu Eu3+
 +  e− 		⇌ Eu2+
 		−0.35 1
In In3+
 + 3 e− 		⇌ In(s) −0.34 3
Tl Tl+
 +  e− 		⇌ Tl(s) −0.34 1
Ge Ge(s) + 4 H+ + 4 e− ⇌ GeH
4(g) 		−0.29 4
Co Co2+
 + 2 e− 		⇌ Co(s) −0.28 2
P H
3PO
4(aq) + 2 H+ + 2 e− 		⇌ H
3PO
3(aq) + H2O 		−0.276 2
N N2(g) + 8 H+ + 6 e− ⇌ 2NH+
4		 −0.27 6
V V3+
 +  e− 		⇌ V2+
 		−0.26 1
Ni Ni2+
 + 2 e− 		⇌ Ni(s) −0.257 2
S 2HSO−
4 + 2 H+ + 2 e−		 ⇌ S2O2−
6 + 2H2O(l)		 −0.253 2 : 790 
As As(s) + 3 H+ + 3 e− ⇌ AsH
3(g) 		−0.23 3
N N2(g) + 5 H+ + 4 e− ⇌ N2H+
5		 −0.23 4 : 789 
Ga Ga+
 +  e− 		⇌ Ga(s) −0.2 1
Ag AgI(s) +  e− ⇌ Ag(s) + I−
 		−0.15224 1
Ge GeO2(s) + 4 H+ + 4 e− ⇌ Ge(s) + 2H2O(l) −0.15 4
Mo MoO
2(s) + 4 H+ + 4 e− 		⇌ Mo(s) + 2H2O −0.15 4
Si Si(s) + 4 H+ + 4 e− ⇌ SiH
4(g) 		−0.14 4
Sn Sn2+
 + 2 e− 		⇌ Sn(s) −0.13 2
O O
2(g) +  H+ +  e− 		⇌ HO•
2(aq) 		−0.13 1
In In+ +  e− ⇌ In(s) −0.126 1 : 788 
Pb Pb2+
 + 2 e− 		⇌ Pb(s) −0.126 2
W WO
2(s) + 4 H+ + 4 e− 		⇌ W(s) + 2H2O −0.12 4
Ge GeO
2(s) + 2 H+ + 2 e− 		⇌ GeO(s) + H2O −0.118 2
P P(red) + 3 H+ + 3 e− ⇌ PH
3(g) 		−0.111 3
C CO
2(g) + 2 H+ + 2 e− 		⇌ HCOOH(aq) −0.11 2
Se Se(s) + 2 H+ + 2 e− ⇌ H
2Se(g) 		−0.11 2 : 790 
C CO
2(g) + 2 H+ + 2 e− 		⇌ CO(g) + H2O −0.11 2
Sn α-SnO(s) + 2 H+ + 2 e− ⇌ Sn(s) + H2O −0.104 2 : 788 
Cu Cu(NH
3)+
2 +  e− 		⇌ Cu(s) + 2NH
3(aq) 		−0.1 1
Nb Nb2O5(s) + 10 H+ + 4 e− ⇌ 2Nb3+
 + 5H2O(l)		 −0.1 4 : 793 
W WO
3(aq) + 6 H+ + 6 e− 		⇌ W(s) + 3H2O −0.09 6
Sn SnO
2(s) + 2 H+ + 2 e− 		⇌ α-SnO(s) + H2O −0.088 2 : 788 
Fe Fe
3O
4(s) + 8 H+ + 8 e− 		⇌ 3Fe(s) + 4H2O −0.085 8
V VOH2+
 +  H+ +  e−		 ⇌ V2+
 + H2O(l)		 −0.082 1 : 793 
P P(white) + 3 H+ + 3 e− ⇌ PH
3(g) 		−0.063 3
N N2O(g) + H2O(l) + 6 H+ + 4 e− ⇌ 2NH3OH+ −0.05 4 : 789 
Fe Fe3+
 + 3 e− 		⇌ Fe(s) −0.04 3
C HCOOH(aq) + 2 H+ + 2 e− ⇌ HCHO(aq) + H2O −0.034 2 : 788 
H 2 H+ + 2 e− ⇌ H
2(g) 		0 2
Ag AgBr(s) +  e− ⇌ Ag(s) + Br−
 		0.07133 1
S S
4O2−
6 + 2 e− 		⇌ 2S
2O2−
3 		0.08 2
N N
2(g) + 2H2O + 6 H+ + 6 e− 		⇌ 2NH
4OH(aq) 		0.092 6
Hg HgO(s) + H2O + 2 e− ⇌ Hg(l) + 2 OH− 0.0977 2
Cu Cu(NH
3)2+
4 +  e− 		⇌ Cu(NH
3)+
2 + 2NH
3(aq) 		0.1 1
Ru Ru(NH
3)3+
6 +  e− 		⇌ Ru(NH
3)2+
6 		0.1 1
N N
2H
4(aq) + 4H2O + 2 e− 		⇌ 2NH+
4 + 4 OH− 		0.11 2
Mo H
2MoO
4(aq) + 6 H+ + 6 e− 		⇌ Mo(s) + 4H2O 0.11 6
Ge Ge4+
 + 4 e− 		⇌ Ge(s) 0.12 4
C C(s) + 4 H+ + 4 e− ⇌ CH
4(g) 		0.13 4
C HCHO(aq) + 2 H+ + 2 e− ⇌ CH
3OH(aq) 		0.13 2
S S(s) + 2 H+ + 2 e− ⇌ H
2S(g) 		0.144 2 : 790 
Sb Sb2O3(s) + 6 H+ + 6 e− ⇌ 2Sb(s) + 3H2O 0.15 6 : 789 
Sn Sn4+
 + 2 e− 		⇌ Sn2+
 		0.151 2
S HSO−
4 + 3 H+ + 2 e− 		⇌ SO
2(aq) + 2H2O 		0.158 2 : 790 
Cu Cu2+
 +  e− 		⇌ Cu+
 		0.159 1
U UO2+
2 +  e− 		⇌ UO+
2 		0.163 1
S SO2−
4 + 4 H+ + 2 e− 		⇌ SO
2(aq) + 2H2O 		0.17 2
Ti TiO2+
 + 2 H+ +  e− 		⇌ Ti3+
 + H2O 		0.19 1
Sb SbO+
 + 2 H+ + 3 e− 		⇌ Sb(s) + H2O 0.2 3
Fe 3Fe
2O
3(s) + 2 H+ + 2 e− 		⇌ 2Fe
3O
4(s) + H2O 		0.22 2 : p.100 
Ag AgCl(s) +  e− ⇌ Ag(s) + Cl−
 		0.22233 1
As H
3AsO
3(aq) + 3 H+ + 3 e− 		⇌ As(s) + 3H2O 0.24 3 : 789 
Ru Ru3+
(aq) +  e− 		⇌ Ru2+
(aq) 		0.249 1
Pb PbO2(s) + H2O + 2 e− ⇌ α-PbO(s) + 2 OH− 0.254 2 : 788 
Ge GeO(s) + 2 H+ + 2 e− ⇌ Ge(s) + H2O 0.26 2
Hg Hg2Cl2(s) + 2 e− ⇌ 2Hg(l) + 2Cl− 0.27 2
U UO+
2 + 4 H+ +  e− 		⇌ U4+
 + 2H2O 		0.273 1
Re Re3+
 + 3 e− 		⇌ Re(s) 0.300 3
At At +  e− ⇌ At− 0.3 1
Bi Bi3+
 + 3 e− 		⇌ Bi(s) 0.308 3
C 2HCNO + 2 H+ + 2 e− ⇌ (CN)2 + 2H2O 0.330 2
Cu Cu2+
 + 2 e− 		⇌ Cu(s) 0.337 2
V VO2+
 + 2 H+ +  e− 		⇌ V3+
 + H2O 		0.337 1 : 793 
Sb Sb2O4(s) + 2 H+ + 2 e− ⇌ Sb2O3(s) + H2O(l) 0.342 2 : 789 
At At+ + 2 e− ⇌ At− 0.36 2
Fe [Fe(CN)
6]3−
 +  e− 		⇌ [Fe(CN)
6]4−
 		0.3704 1
C (CN)2 + 2 H+ + 2 e− ⇌ 2HCN 0.373 2
P (H2PO3)2(aq) + 2 H+ + 2 e− ⇌ 2H3PO3 0.38 2 : 789 
S 2SO2(aq) + 2 H+ + 2 e− ⇌ S2O2−
3 + H2O(l)		 0.4 2 : 790 
O O
2(g) + 2H2O + 4 e− 		⇌ 4 OH−(aq) 0.401 4
Mo H
2MoO
4 + 6 H+ + 3 e− 		⇌ Mo3+
 + 4H2O 		0.43 3
Ru Ru2+
(aq) + 2 e− 		⇌ Ru 0.455 2
V VO(OH)+ + 2 H+ +  e− ⇌ VOH2+
 + H2O(l)		 0.481 1 : 793 
C CH
3OH(aq) + 2 H+ + 2 e− 		⇌ CH
4(g) + H2O 		0.5 2
S SO
2(aq) + 4 H+ + 4 e− 		⇌ S(s) + 2H2O 0.5 4 : 790 
S 4SO
2(aq) + 4 H+ + 6 e−		 ⇌ S4O2−
6 + 2H2O(l)		 0.51 6
Cu Cu+
 +  e− 		⇌ Cu(s) 0.52 1
C CO(g) + 2 H+ + 2 e− ⇌ C(s) + H2O 0.52 2 : 788 
I I−
3 + 2 e− 		⇌ 3I−
 		0.53 2
Te TeO2(s) + 4 H+ + 4 e− ⇌ Te(s) + 2H2O(l) 0.53 4 : 790 
Cu Cu2+
 + Cl− +  e−		 ⇌ CuCl(s) 0.54 1
I I
2(s) + 2 e− 		⇌ 2I−
 		0.54 2
Au [AuI
4]−
 + 3 e− 		⇌ Au(s) + 4I−
 		0.56 3
As H
3AsO
4(aq) + 2 H+ + 2 e− 		⇌ H
3AsO
3(aq) + H2O 		0.56 2 : 789 
S S2O2−
6 + 4 H+ + 2 e−		 ⇌ 2H2SO3 0.569 2 : 790 
Au [AuI
2]−
 +  e− 		⇌ Au(s) + 2I−
 		0.58 1
Mn MnO−
4 + 2H2O + 3 e− 		⇌ MnO
2(s) + 4 OH− 		0.595 3
S S
2O2−
3 + 6 H+ + 4 e− 		⇌ 2S(s) + 3H2O 0.6 4 : 790 
Fe Fc+
 +  e−		 ⇌ Fc(s) 0.63 1 Substantial literature variation
Mo H
2MoO
4(aq) + 2 H+ + 2 e− 		⇌ MoO
2(s) + 2H2O 		0.65 2
N HN3(aq) + 11 H+ + 8 e− ⇌ 3NH+
4		 0.69 8
O O
2(g) + 2 H+ + 2 e− 		⇌ H
2O
2(aq) 		0.695 2
Sb Sb2O5(s) + 4 H+ + 4 e− ⇌ Sb2O3(s) + 2H2O 0.699 4 : 789 
C + 2 H+ + 2 e− ⇌ 0.6992 2
V H2V10O4−
28 + 24 H+ + 10 e−		 ⇌ 10VO(OH)+ + 8H2O(l) 0.723 10 : 793 
Pt PtCl2−
6 + 2 e− 		⇌ PtCl2−
4 + 2Cl−
 		0.726 2
Fe Fe
2O
3(s) + 6 H+ + 2 e− 		⇌ 2Fe2+
 + 3H2O 		0.728 2 : p.100 
Se H
2SeO
3(aq) + 4 H+ + 4 e− 		⇌ Se(s) + 3H2O 0.74 4
At AtO+ + 2 H+ + 2 e− ⇌ At+ + H2O 0.74 2
Tl Tl3+
 + 3 e− 		⇌ Tl(s) 0.741 3
No No3+
 +  e− 		⇌ No2+
 		0.75 1
Pt PtCl2−
4 + 2 e− 		⇌ Pt(s) + 4Cl−
 		0.758 2
Br BrO− + H2O(l) + 2 e− ⇌ Br− + 2 OH− 0.76 2 : 791 
Po Po4+ + 4 e− ⇌ Po 0.76 4
S (SCN)2 + 2 e− ⇌ 2SCN− 0.769 2
Fe Fe3+
 +  e− 		⇌ Fe2+
 		0.771 1
Hg Hg2+
2 + 2 e− 		⇌ 2Hg(l) 0.7973 2
Ag Ag+
 +  e− 		⇌ Ag(s) 0.7996 1
N 2NO−
3(aq) + 4 H+ + 2 e− 		⇌ N
2O
4(g) + 2H2O 		0.803 2 : 789 
Fe 2FeO2−
4 + 5H2O + 6 e− 		⇌ Fe
2O
3(s) + 10 OH− 		0.81 6
Au [AuBr
4]−
 + 3 e− 		⇌ Au(s) + 4Br−
 		0.85 3
Hg Hg2+
 + 2 e− 		⇌ Hg(l) 0.85 2
Ir [IrCl
6]2−
 +  e− 		⇌ [IrCl
6]3−
 		0.87 1 : 153 
Mn MnO−
4 +  H+ +  e− 		⇌ HMnO−
4 		0.9 1
Po Po4+ + 2 e− ⇌ Po2+ 0.9 2
Hg 2Hg2+
 + 2 e− 		⇌ Hg2+
2 		0.91 2
Pd Pd2+
 + 2 e− 		⇌ Pd(s) 0.915 2
Au [AuCl
4]−
 + 3 e− 		⇌ Au(s) + 4Cl−
 		0.93 3
N NO−
3 + 3 H+ + 2 e−		 ⇌ HNO2(aq) 0.94 2 : 789 
Mn MnO
2(s) + 4 H+ +  e− 		⇌ Mn3+
 + 2H2O 		0.95 1
N NO−
3(aq) + 4 H+ + 3 e− 		⇌ NO(g) + 2H2O(l) 0.958 3
Au [AuBr
2]−
 +  e− 		⇌ Au(s) + 2Br−
 		0.96 1
Fe Fe
3O
4(s) + 8 H+ + 2 e− 		⇌ 3Fe2+
 + 4H2O 		0.98 2 : p.100 
Xe [HXeO
6]3−
 + 2H2O + 2 e− 		⇌ [HXeO
4]−
 + 4 OH− 		0.99 2 : 792 
N HNO2(aq) +  H+ +  e− ⇌ NO(g) + H2O(l) 0.996 1 : 789 
At HAtO +  H+ +  e− ⇌ At + H2O 1.0 1
V [VO
2]+
(aq) + 2 H+ +  e− 		⇌ [VO]2+
(aq) + H2O 		1 1
Te H
6TeO
6(aq) + 2 H+ + 2 e− 		⇌ TeO
2(s) + 4H2O 		1.02 2
N NO2(g) + 2 H+ + 2 e− ⇌ NO(g) + H2O(l) 1.03 2
Br Br−
3 + 2 e−		 ⇌ 3Br−
 1.05 2
Sb Sb2O5(s) + 2 H+ + 2 e− ⇌ Sb2O4(s) + H2O(l) 1.055 2 : 789 
I ICl−
2 +  e−		 ⇌ 2Cl−
 + I(s)		 1.06 1
Br Br
2(l) + 2 e− 		⇌ 2Br−
 		1.066 2
N N2O4(g) + 2 H+ + 2 e− ⇌ 2HNO2 1.07 2 : 789 
Br Br
2(aq) + 2 e− 		⇌ 2Br−
 		1.0873 2
Ru RuO
2 + 4 H+ + 2 e− 		⇌ Ru2+
(aq) + 2H2O 		1.120 2
Cu Cu2+
 + 2CN−
 +  e− 		⇌ Cu(CN)−
2 		1.12 1
I IO−
3 + 5 H+ + 4 e− 		⇌ HIO(aq) + 2H2O 1.13 4 : 791 
O H2O2(aq) +  H+ +  e− ⇌ H2O(l) + HO• 1.14 1 : 790 
Au [AuCl
2]−
 +  e− 		⇌ Au(s) + 2Cl−
 		1.15 1
Se HSeO−
4 + 3 H+ + 2 e− 		⇌ H
2SeO
3(aq) + H2O 		1.15 2 : 790 
Ag Ag
2O(s) + 2 H+ + 2 e− 		⇌ 2Ag(s) + H2O 1.17 2
Cl ClO−
3 + 2 H+ +  e− 		⇌ ClO
2(g) + H2O 		1.175 1 : 791 
Xe [HXeO
6]3−
 + 5H2O + 8 e− 		⇌ Xe(g) + 11 OH− 1.18 8
Pt Pt2+
 + 2 e− 		⇌ Pt(s) 1.188 2
Cl ClO
2(g) +  H+ +  e− 		⇌ HClO
2(aq) 		1.19 1
I 2IO−
3 + 12 H+ + 10 e− 		⇌ I
2(s) + 6H2O 		1.2 10
Mn MnO
2(s) + 4 H+ + 2 e− 		⇌ Mn2+
 + 2H2O 		1.224 2
O O
2(g) + 4 H+ + 4 e− 		⇌ 2H2O 1.229 4
N N2H+
5 + 3 H+ + 2 e−		 ⇌ 2NH+
4		 1.28 2 : 789 
Cl ClO−
4 + 2 H+ + 2 e− 		⇌ ClO−
3 + H2O 		1.23 2
Ru [Ru(bipy)
3]3+
 +  e− 		⇌ [Ru(bipy)
3]2+
 		1.24 1
Xe [HXeO
4]−
 + 3H2O + 6 e− 		⇌ Xe(g) + 7 OH− 1.24 6 : 792 
N 2NO−
3 + 12 H+ + 10 e−		 ⇌ N2(g) + 6H2O(l) 1.25 10 : 789 
Tl Tl3+
 + 2 e− 		⇌ Tl+
 		1.25 2 : 788 
N 2HNO2(aq) + 4 H+ + 4 e− ⇌ N2O(g) + 3H2O(l) 1.297 4 : 789 
Cr Cr
2O2−
7 + 14 H+ + 6 e− 		⇌ 2Cr3+
 + 7H2O 		1.33 6 : 1005 
N NH3OH+ + 2 H+ + 2 e− ⇌ NH+
4 + H2O(l)		 1.35 2 : 789 
Cl Cl
2(g) + 2 e− 		⇌ 2Cl−
 		1.36 2
Ru RuO−
4(aq) + 8 H+ + 5 e− 		⇌ Ru2+
(aq) + 4H2O 		1.368 5
Ru RuO
4 + 4 H+ + 4 e− 		⇌ RuO
2 + 2H2O 		1.387 4
Co CoO
2(s) + 4 H+ +  e− 		⇌ Co3+
 + 2H2O 		1.42 1
N 2NH
3OH+
 +  H+ + 2 e− 		⇌ N
2H+
5 + 2H2O 		1.42 2
I 2HIO(aq) + 2 H+ + 2 e− ⇌ I
2(s) + 2H2O 		1.44 2 : 791 
Br BrO−
3 + 5 H+ + 4 e− 		⇌ HBrO(aq) + 2H2O 1.447 4 : 791 
Pb β-PbO
2(s) + 4 H+ + 2 e− 		⇌ Pb2+
 + 2H2O 		1.46 2
Pb α-PbO
2(s) + 4 H+ + 2 e− 		⇌ Pb2+
 + 2H2O 		1.468 2
Br 2BrO−
3 + 12 H+ + 10 e− 		⇌ Br
2(l) + 6H2O 		1.48 10
At HAtO3 + 4 H+ + 4 e− ⇌ HAtO + 2H2O 1.5 4
Mn MnO−
4 + 8 H+ + 5 e− 		⇌ Mn2+
 + 4H2O 		1.51 5
O HO•
2 +  H+ +  e− 		⇌ H
2O
2(aq) 		1.51 1
Au Au3+
 + 3 e− 		⇌ Au(s) 1.52 3
Ru RuO2−
4(aq) + 8 H+ + 4 e− 		⇌ Ru2+
(aq) + 4H2O 		1.563 4
N 2NO(g) + 2 H+ + 2 e− ⇌ N2O(g) + H2O(l) 1.59 2 : 789 
Ni NiO
2(s) + 2 H+ + 2 e− 		⇌ Ni2+
 + 2 OH− 		1.59 2
Ce Ce4+
 +  e− 		⇌ Ce3+
 		1.61 1
Cl 2HClO(aq) + 2 H+ + 2 e− ⇌ Cl
2(g) + 2H2O 		1.63 2
I IO−
4 + 2 H+ + 2 e− 		⇌ IO−
3 + H2O 		1.64 2
Ag Ag
2O
3(s) + 6 H+ + 4 e− 		⇌ 2Ag+
 + 3H2O 		1.67 4
Cl HClO
2(aq) + 2 H+ + 2 e− 		⇌ HClO(aq) + H2O 1.67 2
Pb Pb4+
 + 2 e− 		⇌ Pb2+
 		1.69 2
Mn MnO−
4 + 4 H+ + 3 e− 		⇌ MnO
2(s) + 2H2O 		1.7 3
Br BrO−
4 + 2 H+ + 2 e− 		⇌ BrO−
3 + H2O 		1.74 2
Ag AgO(s) + 2 H+ +  e− ⇌ Ag+
 + H2O 		1.77 1
N N2O(g) + 2 H+ + 2 e− ⇌ N2(g) + H2O(l) 1.77 2 : 789 
O H
2O
2(aq) + 2 H+ + 2 e− 		⇌ 2H2O 1.78 2
Au Au+
 +  e− 		⇌ Au(s) 1.83 1
Co Co3+
 +  e− 		⇌ Co2+
 		1.92 1
Ag Ag2+
 +  e− 		⇌ Ag+
 		1.98 1
O S
2O2−
8 + 2 e− 		⇌ 2SO2−
4 		2.01 2
O O
3(g) + 2 H+ + 2 e− 		⇌ O
2(g) + H2O 		2.075 2
Mn HMnO−
4 + 3 H+ + 2 e− 		⇌ MnO
2(s) + 2H2O 		2.09 2
Xe XeO
3(aq) + 6 H+ + 6 e− 		⇌ Xe(g) + 3H2O 2.12 6 : 792 
Xe H
4XeO
6(aq) + 8 H+ + 8 e− 		⇌ Xe(g) + 6H2O 2.18 8 : 792 
Fe FeO2−
4 + 8 H+ + 3 e− 		⇌ Fe3+
 + 4H2O 		2.2 3
Xe XeF
2(aq) + 2 H+ + 2 e− 		⇌ Xe(g) + 2HF(aq) 2.32 2
O HO• +  H+ +  e− ⇌ H2O(l) 2.38 1 : 790 
Xe H
4XeO
6(aq) + 2 H+ + 2 e− 		⇌ XeO
3(aq) + 3H2O 		2.42 2 : 792 
F F
2(g) + 2 e− 		⇌ 2F−
 		2.87 2 : 153 
Cm Cm4+ + e– ⇌ Cm3+ 3.0 1 Estimated
F F
2(g) + 2 H+ + 2 e− 		⇌ 2HF(aq) 3.077 2
Tb Tb4+ + e– ⇌ Tb3+ 3.1 1 Estimated
Pr Pr4+ + e– ⇌ Pr3+ 3.2 1 Estimated
Kr KrF
2(aq) + 2 e− 		⇌ Kr(g) + 2F−
(aq) 		3.27 2 Estimated

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

wikipedia, wiki, encyclopedia, book, library, article, read, free download, Information about Standard electrode potential (data page), What is Standard electrode potential (data page)? What does Standard electrode potential (data page) mean?

Home Page | Go up