H Standard Reduction Potentials (by name)
Data from CRC Handbook4. E° given at 25 °C.
Half-Reaction | E° (V) |
---|---|
Ac3+ + 3e– → Ac | -2.2 |
Ag+ + e– → Ag | 0.7996 |
Ag2+ + e– → Ag | 1.98 |
Ag(ac) + e– → Ag + (ac)– | 0.643 |
AgBr + e– → Ag + Br– | 0.07133 |
AgCl + e– → Ag + Cl– | 0.22233 |
Ag2CrO4 + 2e– → 2Ag + CrO42– | 0.447 |
AgI + e– → Ag + I– | -0.15224 |
Ag2S + 2e– → 2Ag + S2– | -0.691 |
Ag2S + 2H+ + 2e– → 2Ag + H2S | -0.0366 |
AgSCN + e– → Ag + SCN– | 0.08951 |
Al3+ + 3e– → Al | -1.662 |
Al(OH)4– + 3e– → Al + 4OH– | -2.328 |
Am3+ + 3e– → Am | -2.048 |
As + 3H+ + 3e– → AsH3 | -0.608 |
H3AsO4 + 2H+ + 2e– → HAsO2 + 2H2O | 0.56 |
Au+ + e– → Au | 1.692 |
Au3+ + 3e– → Au | 1.498 |
H3BO3 + 3H+ + 3e– → B + 3H2O | -0.8698 |
Ba2+ + 2e– → Ba | -2.912 |
Be2+ + 2e– → Be | -1.847 |
Bi3+ + 3e– → Bi | 0.308 |
BiO+ + 2H+ + 3e– → Bi + H2O | 0.32 |
Br2(aq) + 2e– → 2Br– | 1.0873 |
Br2(l) + 2e– → 2Br– | 1.066 |
BrO3– + 6H+ + 5e– → Br2 + 3H2O | 1.482 |
BrO3– + 6H+ + 6e– → Br– + 3H2O | 1.423 |
CO2 + 2H+ + 2e– → HCO2H | -0.199 |
Ca2+ + 2e– → Ca | -2.868 |
Ca(OH)2 + 2e– → Ca + 2OH– | -3.02 |
Cd2+ + 2e– → Cd | -0.403 |
CdSO4 + 2e– → Cd + SO42– | -0.246 |
Cd(OH)42– + 2e– → Cd + 4OH– | -0.658 |
Ce3+ + 3e– → Ce | -2.336 |
Ce4– + e– → Ce3+ | 1.72 |
Cl2(g) + 2e– → 2Cl– | 1.35827 |
HClO + H+ + e– → Cl2 + H2O | 1.611 |
HClO + H+ + 2e– → Cl– + H2O | 1.482 |
ClO– + H2O + 2e– → Cl– + 2OH– | 0.81 |
ClO3– + 6H+ + 5e– → Cl2 + 3H2O | 1.47 |
ClO3– + 6H+ + 6e– → Cl– + 3H2O | 1.451 |
ClO4– + 8H+ + 7e– → Cl2 + 4H2O | 1.39 |
ClO4– + 8H+ + 8e– → Cl– + 4H2O | 1.389 |
Co2+ + 2e– → Co | -0.28 |
Co3+ + e– → Co2+ | 1.92 |
Cr2+ + 2e– → Cr | -0.913 |
Cr3+ + e– → Cr2+ | -0.407 |
Cr3+ + 3e– → Cr | -0.744 |
Cr2O7– + 14H+ + 6e– → 2Cr3+ + 7H2O | 1.232 |
CrO42– + 4H2O + 3e– → Cr(OH)3 + 5OH– | -0.13 |
Cs+ + e– → Cs | -3.026 |
Cu+ + e– → Cu | 0.521 |
Cu2+ + e– → Cu+ | 0.153 |
Cu2+ + 2e– → Cu | 0.3419 |
CuI2– + e– → Cu + 2I– | 0 |
Cu2O + H2O + 2e– → 2Cu + 2OH– | -0.36 |
Dy3+ + 3e– → Dy | -2.295 |
Er3+ + 3e– → Er | -2.331 |
Es3+ + 3e– → Es | -1.91 |
Eu2+ + 2e– → Eu | -2.812 |
Eu3+ + 3e– → Eu | -1.991 |
F2 + 2e– → 2F– | 2.866 |
Fe2+ + 2e– → Fe | -0.447 |
Fe3+ + 3e– → Fe | -0.037 |
Fe3+ + e– → Fe2+ | 0.771 |
[Fe(CN)6]3– + e– → [Fe(CN)6]4– | 0.358 |
Fe(OH)3 + e– → Fe(OH)2 + OH– | -0.56 |
Fm3+ + 3e– → Fm | -1.89 |
Fm2+ + 2e– → Fm | -2.3 |
Ga3+ + 3e– → Ga | -0.549 |
Gd3+ + 3e– → Gd | -2.279 |
Ge2+ + 2e– → Ge | 0.24 |
Ge4+ + 4e– → Ge | 0.124 |
2H+ + 2e– → H2 | 0 |
H2 + 2e– → 2H– | -2.23 |
2H2O + 2e– → H2 + 2OH– | -0.8277 |
H2O2 + 2H+ + 2e– → 2H2O | 1.776 |
Hf4+ + 4e– → Hf | -1.55 |
Hg2+ + 2e– → Hg | 0.851 |
2Hg2+ + 2e– → Hg22+ | 0.92 |
Hg2Cl2 + 2e– → 2Hg + 2Cl– | 0.26808 |
Ho2+ + 2e– → Ho | -2.1 |
Ho3+ + 3e– → Ho | -2.33 |
I2 + 2e– → 2I– | 0.5355 |
I3– + 2e– → 3I– | 0.536 |
2IO3– + 12H+ + 10e– → I2 + 6H2O | 1.195 |
IO3– + 6H+ + 6e– → I– + 3H2O | 1.085 |
In+ + e– → In | -0.14 |
In3+ + 2e– → In+ | -0.443 |
In3+ + 3e– → In | -0.3382 |
Ir3+ + 3e– → Ir | 1.156 |
K+ + e– → K | -2.931 |
La3+ + 3e– → La | -2.379 |
Li+ + e– → Li | -3.0401 |
Lr3+ + 3e– → Lr | -1.96 |
Lu3+ + 3e– → Lu | -2.28 |
Md3+ + 3e– → Md | -1.65 |
Md2+ + 2e– → Md | -2.4 |
Mg2+ + 2e– → Mg | -2.372 |
Mn2+ + 2e– → Mn | -1.185 |
MnO2 + 4H+ + 2e– → Mn2+ + 2H2O | 1.224 |
MnO4– + 8H+ + 5e– → Mn2+ + 4H2O | 1.507 |
MnO4– + 2H2O + 3e– → MnO2 + 4OH– | 0.595 |
Mo3+ + 3e– → Mo | -0.2 |
N2 + 2H2O + 6H+ + 6e– → 2NH4OH | 0.092 |
HNO2 + H+ + e– → NO + H2O | 0.983 |
NO3– + 4H+ + 3e– → NO + 2H2O | 0.957 |
Na+ + e– → Na | -2.71 |
Nb3+ + 3e– → Nb | -1.099 |
Nd3+ + 3e– → Nd | -2.323 |
Ni2+ + 2e– → Ni | -0.257 |
No3+ + 3e– → No | -1.2 |
No2+ + 2e– → No | -2.5 |
Np3+ + 3e– → Np | -1.856 |
O2 + 2H+ + 2e– → H2O2 | 0.695 |
O2 + 4H+ + 4e– → 2H2O | 1.229 |
O2 + 2H2O + 2e– → H2O2 + 2OH– | -0.146 |
O3 + 2H+ + 2e– → O2 + H2O | 2.076 |
OsO4 + 8H+ + 8e– → Os + 4H2O | 0.838 |
P + 3H2O + 3e– → PH3(g) + 3OH– | -0.87 |
PO43– + 2H2O + 2e– → HPO32– + 3OH– | -1.05 |
Pa3+ + 3e– → Pa | -1.34 |
Pa4+ + 4e– → Pa | -1.49 |
Pb2+ + 2e– → Pb | -0.1262 |
PbO + H2O + 2e– → Pb + 2OH– | -0.58 |
PbO2 + SO42– + 4H+ + 2e– → PbSO4 + 2H2O | 1.6913 |
PbSO4 + 2e– → Pb + SO42– | -0.3588 |
Pd2+ + 2e– → Pd | 0.951 |
Pm3+ + 3e– → Pm | -2.3 |
Po4+ + 4e– → Po | 0.76 |
Pr3+ + 3e– → Pr | -2.353 |
Pt2+ + 2e– → Pt | 1.18 |
[PtCl4]2– + 2e– → Pt + 4Cl– | 0.755 |
Pu3+ + 3e– → Pu | -2.031 |
Ra2+ + 2e– → Ra | -2.8 |
Rb+ + e– → Rb | -2.98 |
Re3+ + 3e– → Re | 0.3 |
Rh3+ + 3e– → Rh | 0.758 |
Ru3+ + e– → Ru2+ | 0.2487 |
S + 2e– → S2– | -0.47627 |
S + 2H+ + 2e– → H2S(aq) | 0.142 |
2S + 2e– → S22– | -0.42836 |
H2SO3 + 4H+ + 4e– → S + 3H2O | 0.449 |
SO42– + H2O + 2e– → SO32– + 2OH– | -0.93 |
Sb + 3H+ + 3e– → SbH3 | -0.51 |
Sc3+ + 3e– → Sc | -2.077 |
Se + 2e– → Se2– | -0.924 |
Se + 2H+ + 2e– → H2Se | -0.082 |
SiF62– + 4e– → Si + 6F– | -1.24 |
Sm3+ + 3e– → Sm | -2.304 |
Sn2+ + 2e– → Sn | -0.1375 |
Sn4+ + 2e– → Sn2+ | 0.151 |
Sr2+ + 2e– → Sr | -2.899 |
Ta3+ + 3e– → Ta | -0.6 |
TcO4– + 4H+ + 3e– → TcO2 + 2H2O | 0.782 |
TcO4– + 8H+ + 7e– → Tc + 4H2O | 0.472 |
Tb3+ + 3e– → Tb | -2.28 |
Te + 2e– → Te2– | -1.143 |
Te4+ + 4e– → Te | 0.568 |
Th4+ + 4e– → Th | -1.899 |
Ti2+ + 2e– → Ti | -1.63 |
Tl+ + e– → Tl | -0.336 |
Tl3+ + 2e– → Tl+ | 1.252 |
Tl3+ + 3e– → Tl | 0.741 |
Tm3+ + 3e– → Tm | -2.319 |
U3+ + 3e– → U | -1.798 |
VO2+ + 2H+ + e– → VO2+ + H2O | 0.991 |
V2O5 + 6H+ + 2e– → 2VO2+ + 3H2O | 0.957 |
W2O5 + 2H+ + 2e– → 2WO2 + H2O | -0.031 |
XeO3 + 6H+ + 6e– → Xe + 3H2O | 2.1 |
Y3+ + 3e– → Y | -2.372 |
Yb3+ + 3e– → Yb | -2.19 |
Zn2+ + 2e– → Zn | -0.7618 |
Zn(OH)42– + 2e– → Zn + 4OH– | -1.199 |
Zn(OH)2 + 2e– → Zn + 2OH– | -1.249 |
ZrO2 + 4H+ + 4e– → Zr + 2H2O | -1.553 |
Zr4+ + 4e– → Zr | -1.45 |
References
(4)
CRC Handbook of Chemistry and Physics, 97th ed.; William M. Haynes, T. J. B., David R. Lide, Ed.; CRC Press, 2016.