# 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 mol/L 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°) must satisfy
    ∆G° = –zFE°,
where z electrons are transferred, and the Faraday constant F is the conversion factor describing Coulombs transferred per mole electrons. Those Gibbs free energy changes can be added.
For example, from Fe$^{2+}$ + 2 e$^−$ ⇌ Fe(s) (–0.44 V), the energy to form one neutral atom of Fe(s) from one Fe$^{2+}$ 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 (∆G$_f$°) for an Fe$^{2+}$ ion, since  e$^−$ and Fe(s) both have zero formation energy.
Data from different sources may cause table inconsistencies. For example: ${\begin{alignedat}{4}&{\ce {Cu+ + e-}}&\rightleftharpoons&{\ce {Cu(s)}}&\quad \quad E_{1}=+0.520{\text{ V}}\\&{\ce {Cu^2+ + 2e-}}&\rightleftharpoons&{\ce {Cu(s)}}&\quad \quad E_{2}=+0.337{\text{ V}}\\&{\ce {Cu^2+ + e-}}&\rightleftharpoons&{\ce {Cu+}}&\quad \quad E_{3}=+0.159{\text{ V}}\end{alignedat}}$ From additivity of Gibbs energies, one must have $2\cdot E_{2}=1\cdot E_{1}+1\cdot E_{3}$ 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 | Half-reaction | Half-reaction | E° (volt) | Electrons transferred | Reference |
| Element | Oxidant | ⇌ | Reductant | E° (volt) | Electrons transferred | Reference |
| Sr | Sr$^+$ +  e$^−$ | ⇌ | Sr(s) | -4.101 | 1 | |
| Ca | Ca$^+$ +  e$^−$ | ⇌ | Ca(s) | -3.8 | 1 | |
| Th | Th$^{4+}$ +  e$^−$ | ⇌ | Th$^{3+}$ | -3.6 | 1 | |
| Pr | Pr$^{3+}$ +  e$^−$ | ⇌ | Pr$^{2+}$ | -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) + 4H$_2$O + 2 e$^−$ | ⇌ | 2NH $_2$OH(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 | Er$^{3+}$ +  e$^−$ | ⇌ | Er$^{2+}$ | -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 | Ba$^{2+}$ + 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 | Sr$^{2+}$ + 2 e$^−$ | ⇌ | Sr(s) | -2.899 | 2 | |
| Sr | Sr(OH) $_2$ + 2 e$^−$ | ⇌ | Sr(s) + 2 OH$^−$ | -2.88 | 2 | |
| Ca | Ca$^{2+}$ + 2 e$^−$ | ⇌ | Ca(s) | -2.868 | 2 | $^{:153}$ |
| Li | Li$^+$ + C $_6$(s) +  e$^−$ | ⇌ | LiC $_6$(s) | -2.84 | 1 | |
| Eu | Eu$^{2+}$ + 2 e$^−$ | ⇌ | Eu(s) | -2.812 | 2 | |
| Ra | Ra$^{2+}$ + 2 e$^−$ | ⇌ | Ra(s) | -2.8 | 2 | |
| Ho | Ho$^{3+}$ +  e$^−$ | ⇌ | Ho$^{2+}$ | -2.8 | 1 | |
| Bk | Bk$^{3+}$ +  e$^−$ | ⇌ | Bk$^{2+}$ | -2.8 | 1 | |
| Yb | Yb$^{2+}$ + 2 e$^−$ | ⇌ | Yb(s) | -2.76 | 2 | |
| Na | Na$^+$ +  e$^−$ | ⇌ | Na(s) | -2.71 | 1 | |
| Mg | Mg$^+$ +  e$^−$ | ⇌ | Mg(s) | -2.7 | 1 | |
| Nd | Nd$^{3+}$ +  e$^−$ | ⇌ | Nd$^{2+}$ | -2.7 | 1 | |
| Mg | Mg(OH) $_2$ + 2 e$^−$ | ⇌ | Mg(s) + 2 OH$^−$ | -2.69 | 2 | |
| Sm | Sm$^{2+}$ + 2 e$^−$ | ⇌ | Sm(s) | -2.68 | 2 | |
| Be | Be $_2$O$^{2−}$ $_3$ + 3H$_2$O + 4 e$^−$ | ⇌ | 2Be(s) + 6 OH$^−$ | -2.63 | 4 | |
| Pm | Pm$^{3+}$ +  e$^−$ | ⇌ | Pm$^{2+}$ | -2.6 | 1 | |
| Dy | Dy$^{3+}$ +  e$^−$ | ⇌ | Dy$^{2+}$ | -2.6 | 1 | |
| No | No$^{2+}$ + 2 e$^−$ | ⇌ | No | -2.5 | 2 | |
| Hf | HfO(OH) $_2$ + H$_2$O + 4 e$^−$ | ⇌ | Hf(s) + 4 OH$^−$ | -2.5 | 4 | |
| Th | Th(OH) $_4$ + 4 e$^−$ | ⇌ | Th(s) + 4 OH$^−$ | -2.48 | 4 | |
| Md | Md$^{2+}$ + 2 e$^−$ | ⇌ | Md | -2.4 | 2 | |
| Tm | Tm$^{2+}$ + 2 e$^−$ | ⇌ | Tm(s) | -2.4 | 2 | |
| La | La$^{3+}$ + 3 e$^−$ | ⇌ | La(s) | -2.379 | 3 | |
| Y | Y$^{3+}$ + 3 e$^−$ | ⇌ | Y(s) | -2.372 | 3 | |
| Mg | Mg$^{2+}$ + 2 e$^−$ | ⇌ | Mg(s) | -2.372 | 2 | |
| Sc | ScF$_3$(aq) + 3 H$^+$ + 3 e$^−$ | ⇌ | Sc(s) + 3HF(aq) | -2.37 | 3 | $^{:792}$ |
| Zr | ZrO(OH) $_2$(s) + H$_2$O + 4 e$^−$ | ⇌ | Zr(s) + 4 OH$^−$ | -2.36 | 4 | |
| Pr | Pr$^{3+}$ + 3 e$^−$ | ⇌ | Pr(s) | -2.353 | 3 | |
| Ce | Ce$^{3+}$ + 3 e$^−$ | ⇌ | Ce(s) | -2.336 | 3 | |
| Er | Er$^{3+}$ + 3 e$^−$ | ⇌ | Er(s) | -2.331 | 3 | |
| Ho | Ho$^{3+}$ + 3 e$^−$ | ⇌ | Ho(s) | -2.33 | 3 | |
| Al | H $_2$AlO$^−$ $_3$ + H$_2$O + 3 e$^−$ | ⇌ | Al(s) + 4 OH$^−$ | -2.33 | 3 | |
| Nd | Nd$^{3+}$ + 3 e$^−$ | ⇌ | Nd(s) | -2.323 | 3 | |
| Tm | Tm$^{3+}$ + 3 e$^−$ | ⇌ | Tm(s) | -2.319 | 3 | |
| Al | Al(OH) $_3$(s) + 3 e$^−$ | ⇌ | Al(s) + 3 OH$^−$ | -2.31 | 3 | |
| Sm | Sm$^{3+}$ + 3 e$^−$ | ⇌ | Sm(s) | -2.304 | 3 | |
| Fm | Fm$^{2+}$ + 2 e$^−$ | ⇌ | Fm | -2.3 | 2 | |
| Am | Am$^{3+}$ +  e$^−$ | ⇌ | Am$^{2+}$ | -2.3 | 1 | |
| Dy | Dy$^{3+}$ + 3 e$^−$ | ⇌ | Dy(s) | -2.295 | 3 | |
| Lu | Lu$^{3+}$ + 3 e$^−$ | ⇌ | Lu(s) | -2.28 | 3 | |
| Sc | ScF$^+$ $_2$ + 2 H$^+$ + 3 e$^−$ | ⇌ | Sc(s) + 2HF(l) | -2.28 | 3 | $^{:792}$ |
| Tb | Tb$^{3+}$ + 3 e$^−$ | ⇌ | Tb(s) | -2.28 | 3 | |
| Gd | Gd$^{3+}$ + 3 e$^−$ | ⇌ | Gd(s) | -2.279 | 3 | |
| H | H $_2$(g) + 2 e$^−$ | ⇌ | 2H$^−$ | -2.23 | 2 | |
| Es | Es$^{2+}$ + 2 e$^−$ | ⇌ | Es(s) | -2.23 | 2 | |
| Pm | Pm$^{2+}$ + 2 e$^−$ | ⇌ | Pm(s) | -2.2 | 2 | |
| Tm | Tm$^{3+}$ +  e$^−$ | ⇌ | Tm$^{2+}$ | -2.2 | 1 | |
| Dy | Dy$^{2+}$ + 2 e$^−$ | ⇌ | Dy(s) | -2.2 | 2 | |
| Ac | Ac$^{3+}$ + 3 e$^−$ | ⇌ | Ac(s) | -2.2 | 3 | |
| Yb | Yb$^{3+}$ + 3 e$^−$ | ⇌ | Yb(s) | -2.19 | 3 | |
| Cf | Cf$^{2+}$ + 2 e$^−$ | ⇌ | Cf(s) | -2.12 | 2 | |
| Nd | Nd$^{2+}$ + 2 e$^−$ | ⇌ | Nd(s) | -2.1 | 2 | |
| Ho | Ho$^{2+}$ + 2 e$^−$ | ⇌ | Ho(s) | -2.1 | 2 | |
| Sc | Sc$^{3+}$ + 3 e$^−$ | ⇌ | Sc(s) | -2.077 | 3 | |
| Al | AlF$^{3−}$ $_6$ + 3 e$^−$ | ⇌ | Al(s) + 6F$^−$ | -2.069 | 3 | |
| Cm | Cm$^{3+}$ + 3 e$^−$ | ⇌ | Cm(s) | -2.04 | 3 | |
| Pu | Pu$^{3+}$ + 3 e$^−$ | ⇌ | Pu(s) | -2.031 | 3 | |
| Pr | Pr$^{2+}$ + 2 e$^−$ | ⇌ | Pr(s) | -2 | 2 | |
| Er | Er$^{2+}$ + 2 e$^−$ | ⇌ | Er(s) | -2 | 2 | |
| Eu | Eu$^{3+}$ + 3 e$^−$ | ⇌ | Eu(s) | -1.991 | 3 | |
| Lr | Lr$^{3+}$ + 3 e$^−$ | ⇌ | Lr | -1.96 | 3 | |
| Cf | Cf$^{3+}$ + 3 e$^−$ | ⇌ | Cf(s) | -1.94 | 3 | |
| Es | Es$^{3+}$ + 3 e$^−$ | ⇌ | Es(s) | -1.91 | 3 | |
| Pa | Pa$^{4+}$ +  e$^−$ | ⇌ | Pa$^{3+}$ | -1.9 | 1 | |
| Am | Am$^{2+}$ + 2 e$^−$ | ⇌ | Am(s) | -1.9 | 2 | |
| Th | Th$^{4+}$ + 4 e$^−$ | ⇌ | Th(s) | -1.899 | 4 | |
| Fm | Fm$^{3+}$ + 3 e$^−$ | ⇌ | Fm | -1.89 | 3 | |
| N | N$_2$(g) + 2H$_2$O(l) + 4 H$^+$ + 2 e$^−$ | ⇌ | 2NH$_3$OH$^+$ | -1.87 | 2 | $^{:789}$ |
| Np | Np$^{3+}$ + 3 e$^−$ | ⇌ | Np(s) | -1.856 | 3 | |
| Be | Be$^{2+}$ + 2 e$^−$ | ⇌ | Be(s) | -1.847 | 2 | |
| P | H $_2$PO$^−$ $_2$ +  e$^−$ | ⇌ | P(s) + 2 OH$^−$ | -1.82 | 1 | |
| U | U$^{3+}$ + 3 e$^−$ | ⇌ | U(s) | -1.798 | 3 | |
| Sr | Sr$^{2+}$ + 2 e$^−$ | ⇌ | Sr(Hg) | -1.793 | 2 | |
| B | H $_2$BO$^−$ $_3$ + H$_2$O + 3 e$^−$ | ⇌ | B(s) + 4 OH$^−$ | -1.79 | 3 | |
| Th | ThO $_2$ + 4 H$^+$ + 4 e$^−$ | ⇌ | Th(s) + 2H$_2$O | -1.789 | 4 | |
| Hf | HfO$^{2+}$ + 2 H$^+$ + 4 e$^−$ | ⇌ | Hf(s) + H$_2$O | -1.724 | 4 | |
| P | HPO$^{2−}$ $_3$ + 2H$_2$O + 3 e$^−$ | ⇌ | P(s) + 5 OH$^−$ | -1.71 | 3 | |
| Si | SiO$^{2−}$ $_3$ + 3H$_2$O + 4 e$^−$ | ⇌ | Si(s) + 6 OH$^−$ | -1.697 | 4 | |
| Al | Al$^{3+}$ + 3 e$^−$ | ⇌ | Al(s) | -1.662 | 3 | |
| Ti | Ti$^{2+}$ + 2 e$^−$ | ⇌ | Ti(s) | -1.63 | 2 | |
| Zr | ZrO $_2$(s) + 4 H$^+$ + 4 e$^−$ | ⇌ | Zr(s) + 2H$_2$O | -1.553 | 4 | |
| Zr | Zr$^{4+}$ + 4 e$^−$ | ⇌ | Zr(s) | -1.45 | 4 | |
| Ti | Ti$^{3+}$ + 3 e$^−$ | ⇌ | Ti(s) | -1.37 | 3 | |
| Ti | TiO(s) + 2 H$^+$ + 2 e$^−$ | ⇌ | Ti(s) + H$_2$O | -1.31 | 2 | $^{:792}$ |
| B | B(OH)$^−$ $_4$ + 4H$_2$O(l) + 8 e$^−$ | ⇌ | BH$^−$ $_4$ + 8 OH$^−$ | -1.24 | 8 | $^{:788}$ |
| Ga | GaO(OH)$^−$ $_2$ + H$_2$O(l) + 3 e$^−$ | ⇌ | Ga(s) + 3 OH$^−$ | -1.22 | 3 | $^{:788}$ |
| Ti | Ti $_2$O $_3$(s) + 2 H$^+$ + 2 e$^−$ | ⇌ | 2TiO(s) + H$_2$O | -1.23 | 2 | $^{:792}$ |
| Zn | Zn(OH)$^{2−}$ $_4$ + 2 e$^−$ | ⇌ | Zn(s) + 4 OH$^−$ | -1.199 | 2 | |
| Mn | Mn$^{2+}$ + 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) + 3H$_2$O(l) + 2 e$^−$ | ⇌ | CH$_3$OH(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$^−$ | ⇌ | Te$^{2−}$ | -1.143 | 2 | |
| V | V$^{2+}$ + 2 e$^−$ | ⇌ | V(s) | -1.13 | 2 | |
| Nb | Nb$^{3+}$ + 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$^−$ | ⇌ | Po$^{2−}$ | -1.021 | 2 | |
| Cr | [Cr(edta)(H$_2$O)]$^−$ +  e$^−$ | ⇌ | [Cr(edta)(H$_2$O)]$^{2−}$ | -0.99 | 1 | $^{:793}$ |
| P | 2H$_3$PO$_4$(aq) + 2 H$^+$ + 2 e$^−$ | ⇌ | (H$_2$PO$_3$)$_2$(aq) + H$_2$O(l) | -0.933 | 2 | $^{:789}$ |
| C | CO$^{2−}$ $_3$ + 3 H$^+$ + 2 e$^−$ | ⇌ | HCO$^−$ $_2$ + H$_2$O(l) | -0.93 | 2 | $^{:788}$ |
| Ti | TiO$^{2+}$ + 2 H$^+$ + 4 e$^−$ | ⇌ | Ti(s) + H$_2$O | -0.93 | 4 | |
| Si | SiO $_2$(quartz) + 4 H$^+$ + 4 e$^−$ | ⇌ | Si(s) + 2H$_2$O | -0.909 | 4 | $^{:788}$ |
| Cr | Cr$^{2+}$ + 2 e$^−$ | ⇌ | Cr(s) | -0.9 | 2 | $^{:793}$ |
| B | B(OH) $_3$(aq) + 3 H$^+$ + 3 e$^−$ | ⇌ | B(s) + 3H$_2$O | -0.89 | 3 | $^{:788}$ |
| Fe | Fe(OH) $_2$(s) + 2 e$^−$ | ⇌ | Fe(s) + 2 OH$^−$ | -0.89 | 2 | |
| Fe | Fe $_2$O $_3$(s) + 3H$_2$O + 2 e$^−$ | ⇌ | 2Fe(OH) $_2$(s) + 2 OH$^−$ | -0.86 | 2 | |
| H | 2H$_2$O + 2 e$^−$ | ⇌ | H $_2$(g) + 2 OH$^−$ | -0.8277 | 2 | |
| Bi | Bi(s) + 3 H$^+$ + 3 e$^−$ | ⇌ | BiH $_3$ | -0.8 | 3 | |
| Zn | Zn$^{2+}$ + 2 e$^−$ | ⇌ | Zn(Hg) | -0.7628 | 2 | |
| Zn | Zn$^{2+}$ + 2 e$^−$ | ⇌ | Zn(s) | -0.7618 | 2 | |
| Ta | Ta $_2$O $_5$(s) + 10 H$^+$ + 10 e$^−$ | ⇌ | 2Ta(s) + 5H$_2$O | -0.75 | 10 | |
| Te | 2Te(s) + 2 e$^−$ | ⇌ | Te$^{2−}$ $_2$ | -0.74 | 2 | $^{:790}$ |
| Ni | Ni(OH) $_2$(s) + 2 e$^−$ | ⇌ | Ni(s) + 2 OH$^−$ | -0.72 | 2 | |
| Nb | Nb$_2$O$_5$(s) + 10 H$^+$ + 10 e$^−$ | ⇌ | 2Nb(s) + 5H$_2$O(l) | -0.7 | 10 | $^{:793}$ |
| Ag | Ag $_2$S(s) + 2 e$^−$ | ⇌ | 2Ag(s) + S$^{2−}$ (aq) | -0.69 | 2 | |
| Te | Te$^{2−}$ $_2$ + 4 H$^+$ + 2 e$^−$ | ⇌ | 2H$_2$Te(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 | Ta$^{3+}$ + 3 e$^−$ | ⇌ | Ta(s) | -0.6 | 3 | |
| Pb | PbO(s) + H$_2$O + 2 e$^−$ | ⇌ | Pb(s) + 2 OH$^−$ | -0.580 | 2 | |
| Ti | 2TiO $_2$(s) + 2 H$^+$ + 2 e$^−$ | ⇌ | Ti $_2$O $_3$(s) + H$_2$O | -0.56 | 2 | $^{:792}$ |
| Ga | Ga$^{3+}$ + 3 e$^−$ | ⇌ | Ga(s) | -0.549 | 3 | |
| U | U$^{4+}$ +  e$^−$ | ⇌ | U$^{3+}$ | -0.52 | 1 | |
| P | H $_3$PO $_2$(aq) +  H$^+$ +  e$^−$ | ⇌ | P(white) + 2H$_2$O | -0.508 | 1 | |
| P | H $_3$PO $_3$(aq) + 2 H$^+$ + 2 e$^−$ | ⇌ | H $_3$PO $_2$(aq) + H$_2$O | -0.499 | 2 | |
| Ni | NiO $_2$(s) + 2H$_2$O + 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 $_3$PO $_3$(aq) + 3 H$^+$ + 3 e$^−$ | ⇌ | P(red) + 3H$_2$O | -0.454 | 3 | |
| Bi | Bi$_2$O$_3$(s) + 3H$_2$O(l) + 6 e$^−$ | ⇌ | Bi(s) + 6 OH$^−$ | -0.452 | 6 | $^{:789}$ |
| Ta | TaF$^{2−}$ $_7$ + 7 H$^+$ + 5 e$^−$ | ⇌ | Ta(s) + 7HF(l) | -0.45 | 5 | $^{:793}$ |
| In | In$^{3+}$ + 2 e$^−$ | ⇌ | In$^+$ | -0.444 | 2 | $^{:788}$ |
| Cu | Cu(CN)$^−$ $_2$ +  e$^−$ | ⇌ | Cu(s) + 2CN$^−$ | -0.44 | 1 | |
| Fe | Fe$^{2+}$ + 2 e$^−$ | ⇌ | Fe(s) | -0.44 | 2 | |
| C | 2CO $_2$(g) + 2 H$^+$ + 2 e$^−$ | ⇌ | HOOCCOOH(aq) | -0.43 | 2 | |
| Cr | Cr$^{3+}$ +  e$^−$ | ⇌ | Cr$^{2+}$ | -0.407 | 1 | |
| Cd | Cd$^{2+}$ + 2 e$^−$ | ⇌ | Cd(s) | -0.4 | 2 | |
| Ti | Ti$^{3+}$ +  e$^−$ | ⇌ | Ti$^{2+}$ | -0.37 | 1 | $^{:792}$ |
| Cu | Cu $_2$O(s) + H$_2$O + 2 e$^−$ | ⇌ | 2Cu(s) + 2 OH$^−$ | -0.36 | 2 | |
| Pb | PbSO $_4$(s) + 2 e$^−$ | ⇌ | Pb(s) + SO$^{2−}$ $_4$ | -0.3588 | 2 | |
| Pb | PbSO $_4$(s) + 2 e$^−$ | ⇌ | Pb(Hg) + SO$^{2−}$ $_4$ | -0.3505 | 2 | |
| Eu | Eu$^{3+}$ +  e$^−$ | ⇌ | Eu$^{2+}$ | -0.35 | 1 | |
| In | In$^{3+}$ + 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 | Co$^{2+}$ + 2 e$^−$ | ⇌ | Co(s) | -0.28 | 2 | |
| P | H $_3$PO $_4$(aq) + 2 H$^+$ + 2 e$^−$ | ⇌ | H $_3$PO $_3$(aq) + H$_2$O | -0.276 | 2 | |
| N | N$_2$(g) + 8 H$^+$ + 6 e$^−$ | ⇌ | 2NH$^+$ $_4$ | -0.27 | 6 | |
| V | V$^{3+}$ +  e$^−$ | ⇌ | V$^{2+}$ | -0.26 | 1 | |
| Ni | Ni$^{2+}$ + 2 e$^−$ | ⇌ | Ni(s) | -0.257 | 2 | |
| S | 2HSO$^−$ $_4$ + 2 H$^+$ + 2 e$^−$ | ⇌ | S$_2$O$^{2−}$ $_6$ + 2H$_2$O(l) | -0.253 | 2 | $^{:790}$ |
| As | As(s) + 3 H$^+$ + 3 e$^−$ | ⇌ | AsH $_3$(g) | -0.23 | 3 | |
| N | N$_2$(g) + 5 H$^+$ + 4 e$^−$ | ⇌ | N$_2$H$^+$ $_5$ | -0.23 | 4 | $^{:789}$ |
| Ga | Ga$^+$ +  e$^−$ | ⇌ | Ga(s) | -0.2 | 1 | |
| Ag | AgI(s) +  e$^−$ | ⇌ | Ag(s) + I$^−$ | -0.15224 | 1 | |
| Ge | GeO$_2$(s) + 4 H$^+$ + 4 e$^−$ | ⇌ | Ge(s) + 2H$_2$O(l) | -0.15 | 4 | |
| Mo | MoO $_2$(s) + 4 H$^+$ + 4 e$^−$ | ⇌ | Mo(s) + 2H$_2$O | -0.15 | 4 | |
| Si | Si(s) + 4 H$^+$ + 4 e$^−$ | ⇌ | SiH $_4$(g) | -0.14 | 4 | |
| Sn | Sn$^{2+}$ + 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 | Pb$^{2+}$ + 2 e$^−$ | ⇌ | Pb(s) | -0.126 | 2 | |
| W | WO $_2$(s) + 4 H$^+$ + 4 e$^−$ | ⇌ | W(s) + 2H$_2$O | -0.12 | 4 | |
| Ge | GeO $_2$(s) + 2 H$^+$ + 2 e$^−$ | ⇌ | GeO(s) + H$_2$O | -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 $_2$Se(g) | -0.11 | 2 | $^{:790}$ |
| C | CO $_2$(g) + 2 H$^+$ + 2 e$^−$ | ⇌ | CO(g) + H$_2$O | -0.11 | 2 | |
| Sn | α-SnO(s) + 2 H$^+$ + 2 e$^−$ | ⇌ | Sn(s) + H$_2$O | -0.104 | 2 | $^{:788}$ |
| Cu | Cu(NH $_3$)$^+$ $_2$ +  e$^−$ | ⇌ | Cu(s) + 2NH $_3$(aq) | -0.1 | 1 | |
| Nb | Nb$_2$O$_5$(s) + 10 H$^+$ + 4 e$^−$ | ⇌ | 2Nb$^{3+}$ + 5H$_2$O(l) | -0.1 | 4 | $^{:793}$ |
| W | WO $_3$(aq) + 6 H$^+$ + 6 e$^−$ | ⇌ | W(s) + 3H$_2$O | -0.09 | 6 | |
| Sn | SnO $_2$(s) + 2 H$^+$ + 2 e$^−$ | ⇌ | α-SnO(s) + H$_2$O | -0.088 | 2 | $^{:788}$ |
| Fe | Fe $_3$O $_4$(s) + 8 H$^+$ + 8 e$^−$ | ⇌ | 3Fe(s) + 4H$_2$O | -0.085 | 8 | |
| V | VOH$^{2+}$ +  H$^+$ +  e$^−$ | ⇌ | V$^{2+}$ + H$_2$O(l) | -0.082 | 1 | $^{:793}$ |
| P | P(white) + 3 H$^+$ + 3 e$^−$ | ⇌ | PH $_3$(g) | -0.063 | 3 | |
| N | N$_2$O(g) + H$_2$O(l) + 6 H$^+$ + 4 e$^−$ | ⇌ | 2NH$_3$OH$^+$ | -0.05 | 4 | $^{:789}$ |
| Fe | Fe$^{3+}$ + 3 e$^−$ | ⇌ | Fe(s) | -0.04 | 3 | |
| C | HCOOH(aq) + 2 H$^+$ + 2 e$^−$ | ⇌ | HCHO(aq) + H$_2$O | -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 $_4$O$^{2−}$ $_6$ + 2 e$^−$ | ⇌ | 2S $_2$O$^{2−}$ $_3$ | 0.08 | 2 | |
| N | N $_2$(g) + 2H$_2$O + 6 H$^+$ + 6 e$^−$ | ⇌ | 2NH $_4$OH(aq) | 0.092 | 6 | |
| Hg | HgO(s) + H$_2$O + 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 $_2$H $_4$(aq) + 4H$_2$O + 2 e$^−$ | ⇌ | 2NH$^+$ $_4$ + 4 OH$^−$ | 0.11 | 2 | |
| Mo | H $_2$MoO $_4$(aq) + 6 H$^+$ + 6 e$^−$ | ⇌ | Mo(s) + 4H$_2$O | 0.11 | 6 | |
| Ge | Ge$^{4+}$ + 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 $_3$OH(aq) | 0.13 | 2 | |
| S | S(s) + 2 H$^+$ + 2 e$^−$ | ⇌ | H $_2$S(g) | 0.144 | 2 | $^{:790}$ |
| Sb | Sb$_2$O$_3$(s) + 6 H$^+$ + 6 e$^−$ | ⇌ | 2Sb(s) + 3H$_2$O | 0.15 | 6 | $^{:789}$ |
| Sn | Sn$^{4+}$ + 2 e$^−$ | ⇌ | Sn$^{2+}$ | 0.151 | 2 | |
| S | HSO$^−$ $_4$ + 3 H$^+$ + 2 e$^−$ | ⇌ | SO $_2$(aq) + 2H$_2$O | 0.158 | 2 | $^{:790}$ |
| Cu | Cu$^{2+}$ +  e$^−$ | ⇌ | Cu$^+$ | 0.159 | 1 | |
| U | UO$^{2+}$ $_2$ +  e$^−$ | ⇌ | UO$^+$ $_2$ | 0.163 | 1 | |
| S | SO$^{2−}$ $_4$ + 4 H$^+$ + 2 e$^−$ | ⇌ | SO $_2$(aq) + 2H$_2$O | 0.17 | 2 | |
| Ti | TiO$^{2+}$ + 2 H$^+$ +  e$^−$ | ⇌ | Ti$^{3+}$ + H$_2$O | 0.19 | 1 | |
| Sb | SbO$^+$ + 2 H$^+$ + 3 e$^−$ | ⇌ | Sb(s) + H$_2$O | 0.2 | 3 | |
| Fe | 3Fe $_2$O $_3$(s) + 2 H$^+$ + 2 e$^−$ | ⇌ | 2Fe $_3$O $_4$(s) + H$_2$O | 0.22 | 2 | $^{:p.100}$ |
| Ag | AgCl(s) +  e$^−$ | ⇌ | Ag(s) + Cl$^−$ | 0.22233 | 1 | |
| As | H $_3$AsO $_3$(aq) + 3 H$^+$ + 3 e$^−$ | ⇌ | As(s) + 3H$_2$O | 0.24 | 3 | $^{:789}$ |
| Ru | Ru$^{3+}$ (aq) +  e$^−$ | ⇌ | Ru$^{2+}$ (aq) | 0.249 | 1 | |
| Pb | PbO$_2$(s) + H$_2$O + 2 e$^−$ | ⇌ | α-PbO(s) + 2 OH$^−$ | 0.254 | 2 | $^{:788}$ |
| Ge | GeO(s) + 2 H$^+$ + 2 e$^−$ | ⇌ | Ge(s) + H$_2$O | 0.26 | 2 | |
| Hg | Hg$_2$Cl$_2$(s) + 2 e$^−$ | ⇌ | 2Hg(l) + 2Cl$^−$ | 0.27 | 2 | |
| U | UO$^+$ $_2$ + 4 H$^+$ +  e$^−$ | ⇌ | U$^{4+}$ + 2H$_2$O | 0.273 | 1 | |
| Re | Re$^{3+}$ + 3 e$^−$ | ⇌ | Re(s) | 0.300 | 3 | |
| At | At +  e$^−$ | ⇌ | At$^−$ | 0.3 | 1 | |
| Bi | Bi$^{3+}$ + 3 e$^−$ | ⇌ | Bi(s) | 0.308 | 3 | |
| C | 2HCNO + 2 H$^+$ + 2 e$^−$ | ⇌ | (CN)$_2$ + 2H$_2$O | 0.330 | 2 | |
| Cu | Cu$^{2+}$ + 2 e$^−$ | ⇌ | Cu(s) | 0.337 | 2 | |
| V | VO$^{2+}$ + 2 H$^+$ +  e$^−$ | ⇌ | V$^{3+}$ + H$_2$O | 0.337 | 1 | $^{:793}$ |
| Sb | Sb$_2$O$_4$(s) + 2 H$^+$ + 2 e$^−$ | ⇌ | Sb$_2$O$_3$(s) + H$_2$O(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 | (H$_2$PO$_3$)$_2$(aq) + 2 H$^+$ + 2 e$^−$ | ⇌ | 2H$_3$PO$_3$ | 0.38 | 2 | $^{:789}$ |
| S | 2SO$_2$(aq) + 2 H$^+$ + 2 e$^−$ | ⇌ | S$_2$O$^{2−}$ $_3$ + H$_2$O(l) | 0.4 | 2 | $^{:790}$ |
| O | O $_2$(g) + 2H$_2$O + 4 e$^−$ | ⇌ | 4 OH$^−$(aq) | 0.401 | 4 | |
| Mo | H $_2$MoO $_4$ + 6 H$^+$ + 3 e$^−$ | ⇌ | Mo$^{3+}$ + 4H$_2$O | 0.43 | 3 | |
| Ru | Ru$^{2+}$ (aq) + 2 e$^−$ | ⇌ | Ru | 0.455 | 2 | |
| V | VO(OH)$^+$ + 2 H$^+$ +  e$^−$ | ⇌ | VOH$^{2+}$ + H$_2$O(l) | 0.481 | 1 | $^{:793}$ |
| C | CH $_3$OH(aq) + 2 H$^+$ + 2 e$^−$ | ⇌ | CH $_4$(g) + H$_2$O | 0.5 | 2 | |
| S | SO $_2$(aq) + 4 H$^+$ + 4 e$^−$ | ⇌ | S(s) + 2H$_2$O | 0.5 | 4 | $^{:790}$ |
| S | 4SO $_2$(aq) + 4 H$^+$ + 8 e$^−$ | ⇌ | S$_4$O$^{2−}$ $_6$ + 2H$_2$O(l) | 0.51 | 8 | |
| Cu | Cu$^+$ +  e$^−$ | ⇌ | Cu(s) | 0.52 | 1 | |
| C | CO(g) + 2 H$^+$ + 2 e$^−$ | ⇌ | C(s) + H$_2$O | 0.52 | 2 | $^{:788}$ |
| I | I$^−$ $_3$ + 2 e$^−$ | ⇌ | 3I$^−$ | 0.53 | 2 | |
| Te | TeO$_2$(s) + 4 H$^+$ + 4 e$^−$ | ⇌ | Te(s) + 2H$_2$O(l) | 0.53 | 4 | $^{:790}$ |
| Cu | Cu$^{2+}$ + 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 $_3$AsO $_4$(aq) + 2 H$^+$ + 2 e$^−$ | ⇌ | H $_3$AsO $_3$(aq) + H$_2$O | 0.56 | 2 | $^{:789}$ |
| S | S$_2$O$^{2−}$ $_6$ + 4 H$^+$ + 2 e$^−$ | ⇌ | 2H$_2$SO$_3$ | 0.569 | 2 | $^{:790}$ |
| Au | [AuI $_2$]$^−$ +  e$^−$ | ⇌ | Au(s) + 2I$^−$ | 0.58 | 1 | |
| Mn | MnO$^−$ $_4$ + 2H$_2$O + 3 e$^−$ | ⇌ | MnO $_2$(s) + 4 OH$^−$ | 0.595 | 3 | |
| S | S $_2$O$^{2−}$ $_3$ + 6 H$^+$ + 4 e$^−$ | ⇌ | 2S(s) + 3H$_2$O | 0.6 | 4 | $^{:790}$ |
| Fe | Fc$^+$ +  e$^−$ | ⇌ | Fc(s) | 0.63 | 1 | Substantial literature variation |
| Mo | H $_2$MoO $_4$(aq) + 2 H$^+$ + 2 e$^−$ | ⇌ | MoO $_2$(s) + 2H$_2$O | 0.65 | 2 | |
| N | HN$_3$(aq) + 11 H$^+$ + 8 e$^−$ | ⇌ | 3NH$^+$ $_4$ | 0.69 | 8 | |
| O | O $_2$(g) + 2 H$^+$ + 2 e$^−$ | ⇌ | H $_2$O $_2$(aq) | 0.695 | 2 | |
| Sb | Sb$_2$O$_5$(s) + 4 H$^+$ + 4 e$^−$ | ⇌ | Sb$_2$O$_3$(s) + 2H$_2$O | 0.699 | 4 | $^{:789}$ |
| C | + 2 H$^+$ + 2 e$^−$ | ⇌ | | 0.6992 | 2 | |
| V | H$_2$V$_{10}$O$^{4−}$ $_{28}$ + 24 H$^+$ + 10 e$^−$ | ⇌ | 10VO(OH)$^+$ + 8H$_2$O(l) | 0.723 | 10 | $^{:793}$ |
| Pt | PtCl$^{2−}$ $_6$ + 2 e$^−$ | ⇌ | PtCl$^{2−}$ $_4$ + 2Cl$^−$ | 0.726 | 2 | |
| Fe | Fe $_2$O $_3$(s) + 6 H$^+$ + 2 e$^−$ | ⇌ | 2Fe$^{2+}$ + 3H$_2$O | 0.728 | 2 | $^{:p.100}$ |
| Se | H $_2$SeO $_3$(aq) + 4 H$^+$ + 4 e$^−$ | ⇌ | Se(s) + 3H$_2$O | 0.74 | 4 | |
| At | AtO$^+$ + 2 H$^+$ + 2 e$^−$ | ⇌ | At$^+$ + H$_2$O | 0.74 | 2 | |
| Tl | Tl$^{3+}$ + 3 e$^−$ | ⇌ | Tl(s) | 0.741 | 3 | |
| No | No$^{3+}$ +  e$^−$ | ⇌ | No$^{2+}$ | 0.75 | 1 | |
| Pt | PtCl$^{2−}$ $_4$ + 2 e$^−$ | ⇌ | Pt(s) + 4Cl$^−$ | 0.758 | 2 | |
| Br | BrO$^−$ + H$_2$O(l) + 2 e$^−$ | ⇌ | Br$^−$ + 2 OH$^−$ | 0.76 | 2 | $^{:791}$ |
| Po | Po$^{4+}$ + 4 e$^−$ | ⇌ | Po | 0.76 | 4 | |
| S | (SCN)$_2$ + 2 e$^−$ | ⇌ | 2SCN$^−$ | 0.769 | 2 | |
| Fe | Fe$^{3+}$ +  e$^−$ | ⇌ | Fe$^{2+}$ | 0.771 | 1 | |
| Hg | Hg$^{2+}$ $_2$ + 2 e$^−$ | ⇌ | 2Hg(l) | 0.7973 | 2 | |
| Ag | Ag$^+$ +  e$^−$ | ⇌ | Ag(s) | 0.7996 | 1 | |
| N | 2NO$^−$ $_3$(aq) + 4 H$^+$ + 2 e$^−$ | ⇌ | N $_2$O $_4$(g) + 2H$_2$O | 0.803 | 2 | $^{:789}$ |
| Fe | 2FeO$^{2−}$ $_4$ + 5H$_2$O + 6 e$^−$ | ⇌ | Fe $_2$O $_3$(s) + 10 OH$^−$ | 0.81 | 6 | |
| Au | [AuBr $_4$]$^−$ + 3 e$^−$ | ⇌ | Au(s) + 4Br$^−$ | 0.85 | 3 | |
| Hg | Hg$^{2+}$ + 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 | Po$^{4+}$ + 2 e$^−$ | ⇌ | Po$^{2+}$ | 0.9 | 2 | |
| Hg | 2Hg$^{2+}$ + 2 e$^−$ | ⇌ | Hg$^{2+}$ $_2$ | 0.91 | 2 | |
| Pd | Pd$^{2+}$ + 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$^−$ | ⇌ | HNO$_2$(aq) | 0.94 | 2 | $^{:789}$ |
| Mn | MnO $_2$(s) + 4 H$^+$ +  e$^−$ | ⇌ | Mn$^{3+}$ + 2H$_2$O | 0.95 | 1 | |
| N | NO$^−$ $_3$(aq) + 4 H$^+$ + 3 e$^−$ | ⇌ | NO(g) + 2H$_2$O(l) | 0.958 | 3 | |
| Au | [AuBr $_2$]$^−$ +  e$^−$ | ⇌ | Au(s) + 2Br$^−$ | 0.96 | 1 | |
| Fe | Fe $_3$O $_4$(s) + 8 H$^+$ + 2 e$^−$ | ⇌ | 3Fe$^{2+}$ + 4H$_2$O | 0.98 | 2 | $^{:p.100}$ |
| Xe | [HXeO $_6$]$^{3−}$ + 2H$_2$O + 2 e$^−$ | ⇌ | [HXeO $_4$]$^−$ + 4 OH$^−$ | 0.99 | 2 | $^{:792}$ |
| N | HNO$_2$(aq) +  H$^+$ +  e$^−$ | ⇌ | NO(g) + H$_2$O(l) | 0.996 | 1 | $^{:789}$ |
| At | HAtO +  H$^+$ +  e$^−$ | ⇌ | At + H$_2$O | 1.0 | 1 | |
| V | [VO $_2$]$^+$ (aq) + 2 H$^+$ +  e$^−$ | ⇌ | [VO]$^{2+}$ (aq) + H$_2$O | 1 | 1 | |
| Te | H $_6$TeO $_6$(aq) + 2 H$^+$ + 2 e$^−$ | ⇌ | TeO $_2$(s) + 4H$_2$O | 1.02 | 2 | |
| N | NO$_2$(g) + 2 H$^+$ + 2 e$^−$ | ⇌ | NO(g) + H$_2$O(l) | 1.03 | 2 | |
| Br | Br$^−$ $_3$ + 2 e$^−$ | ⇌ | 3Br$^−$ | 1.05 | 2 | |
| Sb | Sb$_2$O$_5$(s) + 2 H$^+$ + 2 e$^−$ | ⇌ | Sb$_2$O$_4$(s) + H$_2$O(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 | N$_2$O$_4$(g) + 2 H$^+$ + 2 e$^−$ | ⇌ | 2HNO$_2$ | 1.07 | 2 | $^{:789}$ |
| Br | Br $_2$(aq) + 2 e$^−$ | ⇌ | 2Br$^−$ | 1.0873 | 2 | |
| Ru | RuO $_2$ + 4 H$^+$ + 2 e$^−$ | ⇌ | Ru$^{2+}$ (aq) + 2H$_2$O | 1.120 | 2 | |
| Cu | Cu$^{2+}$ + 2CN$^−$ +  e$^−$ | ⇌ | Cu(CN)$^−$ $_2$ | 1.12 | 1 | |
| I | IO$^−$ $_3$ + 5 H$^+$ + 4 e$^−$ | ⇌ | HIO(aq) + 2H$_2$O | 1.13 | 4 | $^{:791}$ |
| O | H$_2$O$_2$(aq) +  H$^+$ +  e$^−$ | ⇌ | H$_2$O(l) + HO• | 1.14 | 1 | $^{:790}$ |
| Au | [AuCl $_2$]$^−$ +  e$^−$ | ⇌ | Au(s) + 2Cl$^−$ | 1.15 | 1 | |
| Se | HSeO$^−$ $_4$ + 3 H$^+$ + 2 e$^−$ | ⇌ | H $_2$SeO $_3$(aq) + H$_2$O | 1.15 | 2 | $^{:790}$ |
| Ag | Ag $_2$O(s) + 2 H$^+$ + 2 e$^−$ | ⇌ | 2Ag(s) + H$_2$O | 1.17 | 2 | |
| Cl | ClO$^−$ $_3$ + 2 H$^+$ +  e$^−$ | ⇌ | ClO $_2$(g) + H$_2$O | 1.175 | 1 | $^{:791}$ |
| Xe | [HXeO $_6$]$^{3−}$ + 5H$_2$O + 8 e$^−$ | ⇌ | Xe(g) + 11 OH$^−$ | 1.18 | 8 | |
| Pt | Pt$^{2+}$ + 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) + 6H$_2$O | 1.2 | 10 | |
| Mn | MnO $_2$(s) + 4 H$^+$ + 2 e$^−$ | ⇌ | Mn$^{2+}$ + 2H$_2$O | 1.224 | 2 | |
| O | O $_2$(g) + 4 H$^+$ + 4 e$^−$ | ⇌ | 2H$_2$O | 1.229 | 4 | |
| N | N$_2$H$^+$ $_5$ + 3 H$^+$ + 2 e$^−$ | ⇌ | 2NH$^+$ $_4$ | 1.28 | 2 | $^{:789}$ |
| Cl | ClO$^−$ $_4$ + 2 H$^+$ + 2 e$^−$ | ⇌ | ClO$^−$ $_3$ + H$_2$O | 1.23 | 2 | |
| Ru | [Ru(bipy) $_3$]$^{3+}$ +  e$^−$ | ⇌ | [Ru(bipy) $_3$]$^{2+}$ | 1.24 | 1 | |
| Xe | [HXeO $_4$]$^−$ + 3H$_2$O + 6 e$^−$ | ⇌ | Xe(g) + 7 OH$^−$ | 1.24 | 6 | $^{:792}$ |
| N | 2NO$^−$ $_3$ + 12 H$^+$ + 10 e$^−$ | ⇌ | N$_2$(g) + 6H$_2$O(l) | 1.25 | 10 | $^{:789}$ |
| Tl | Tl$^{3+}$ + 2 e$^−$ | ⇌ | Tl$^+$ | 1.25 | 2 | $^{:788}$ |
| N | 2HNO$_2$(aq) + 4 H$^+$ + 4 e$^−$ | ⇌ | N$_2$O(g) + 3H$_2$O(l) | 1.297 | 4 | $^{:789}$ |
| Cr | Cr $_2$O$^{2−}$ $_7$ + 14 H$^+$ + 6 e$^−$ | ⇌ | 2Cr$^{3+}$ + 7H$_2$O | 1.33 | 6 | $^{:1005}$ |
| N | NH$_3$OH$^+$ + 2 H$^+$ + 2 e$^−$ | ⇌ | NH$^+$ $_4$ + H$_2$O(l) | 1.35 | 2 | $^{:789}$ |
| Cl | Cl $_2$(g) + 2 e$^−$ | ⇌ | 2Cl$^−$ | 1.36 | 2 | |
| Ru | RuO$^−$ $_4$(aq) + 8 H$^+$ + 5 e$^−$ | ⇌ | Ru$^{2+}$ (aq) + 4H$_2$O | 1.368 | 5 | |
| Ru | RuO $_4$ + 4 H$^+$ + 4 e$^−$ | ⇌ | RuO $_2$ + 2H$_2$O | 1.387 | 4 | |
| Co | CoO $_2$(s) + 4 H$^+$ +  e$^−$ | ⇌ | Co$^{3+}$ + 2H$_2$O | 1.42 | 1 | |
| N | 2NH $_3$OH$^+$ +  H$^+$ + 2 e$^−$ | ⇌ | N $_2$H$^+$ $_5$ + 2H$_2$O | 1.42 | 2 | |
| I | 2HIO(aq) + 2 H$^+$ + 2 e$^−$ | ⇌ | I $_2$(s) + 2H$_2$O | 1.44 | 2 | $^{:791}$ |
| Br | BrO$^−$ $_3$ + 5 H$^+$ + 4 e$^−$ | ⇌ | HBrO(aq) + 2H$_2$O | 1.447 | 4 | $^{:791}$ |
| Pb | β-PbO $_2$(s) + 4 H$^+$ + 2 e$^−$ | ⇌ | Pb$^{2+}$ + 2H$_2$O | 1.46 | 2 | |
| Pb | α-PbO $_2$(s) + 4 H$^+$ + 2 e$^−$ | ⇌ | Pb$^{2+}$ + 2H$_2$O | 1.468 | 2 | |
| Br | 2BrO$^−$ $_3$ + 12 H$^+$ + 10 e$^−$ | ⇌ | Br $_2$(l) + 6H$_2$O | 1.48 | 10 | |
| At | HAtO$_3$ + 4 H$^+$ + 4 e$^−$ | ⇌ | HAtO + 2H$_2$O | 1.5 | 4 | |
| Mn | MnO$^−$ $_4$ + 8 H$^+$ + 5 e$^−$ | ⇌ | Mn$^{2+}$ + 4H$_2$O | 1.51 | 5 | |
| O | HO$^•$ $_2$ +  H$^+$ +  e$^−$ | ⇌ | H $_2$O $_2$(aq) | 1.51 | 1 | |
| Au | Au$^{3+}$ + 3 e$^−$ | ⇌ | Au(s) | 1.52 | 3 | |
| Ru | RuO$^{2−}$ $_4$(aq) + 8 H$^+$ + 4 e$^−$ | ⇌ | Ru$^{2+}$ (aq) + 4H$_2$O | 1.563 | 4 | |
| N | 2NO(g) + 2 H$^+$ + 2 e$^−$ | ⇌ | N$_2$O(g) + H$_2$O(l) | 1.59 | 2 | $^{:789}$ |
| Ni | NiO $_2$(s) + 2 H$^+$ + 2 e$^−$ | ⇌ | Ni$^{2+}$ + 2 OH$^−$ | 1.59 | 2 | |
| Ce | Ce$^{4+}$ +  e$^−$ | ⇌ | Ce$^{3+}$ | 1.61 | 1 | |
| Cl | 2HClO(aq) + 2 H$^+$ + 2 e$^−$ | ⇌ | Cl $_2$(g) + 2H$_2$O | 1.63 | 2 | |
| I | IO$^−$ $_4$ + 2 H$^+$ + 2 e$^−$ | ⇌ | IO$^−$ $_3$ + H$_2$O | 1.64 | 2 | |
| Ag | Ag $_2$O $_3$(s) + 6 H$^+$ + 4 e$^−$ | ⇌ | 2Ag$^+$ + 3H$_2$O | 1.67 | 4 | |
| Cl | HClO $_2$(aq) + 2 H$^+$ + 2 e$^−$ | ⇌ | HClO(aq) + H$_2$O | 1.67 | 2 | |
| Pb | Pb$^{4+}$ + 2 e$^−$ | ⇌ | Pb$^{2+}$ | 1.69 | 2 | |
| Mn | MnO$^−$ $_4$ + 4 H$^+$ + 3 e$^−$ | ⇌ | MnO $_2$(s) + 2H$_2$O | 1.7 | 3 | |
| Br | BrO$^−$ $_4$ + 2 H$^+$ + 2 e$^−$ | ⇌ | BrO$^−$ $_3$ + H$_2$O | 1.74 | 2 | |
| Ag | AgO(s) + 2 H$^+$ +  e$^−$ | ⇌ | Ag$^+$ + H$_2$O | 1.77 | 1 | |
| N | N$_2$O(g) + 2 H$^+$ + 2 e$^−$ | ⇌ | N$_2$(g) + H$_2$O(l) | 1.77 | 2 | $^{:789}$ |
| O | H $_2$O $_2$(aq) + 2 H$^+$ + 2 e$^−$ | ⇌ | 2H$_2$O | 1.78 | 2 | |
| Au | Au$^+$ +  e$^−$ | ⇌ | Au(s) | 1.83 | 1 | |
| Co | Co$^{3+}$ +  e$^−$ | ⇌ | Co$^{2+}$ | 1.92 | 1 | |
| Ag | Ag$^{2+}$ +  e$^−$ | ⇌ | Ag$^+$ | 1.98 | 1 | |
| O | S $_2$O$^{2−}$ $_8$ + 2 e$^−$ | ⇌ | 2SO$^{2−}$ $_4$ | 2.01 | 2 | |
| O | O $_3$(g) + 2 H$^+$ + 2 e$^−$ | ⇌ | O $_2$(g) + H$_2$O | 2.075 | 2 | |
| Mn | HMnO$^−$ $_4$ + 3 H$^+$ + 2 e$^−$ | ⇌ | MnO $_2$(s) + 2H$_2$O | 2.09 | 2 | |
| Xe | XeO $_3$(aq) + 6 H$^+$ + 6 e$^−$ | ⇌ | Xe(g) + 3H$_2$O | 2.12 | 6 | $^{:792}$ |
| Xe | H $_4$XeO $_6$(aq) + 8 H$^+$ + 8 e$^−$ | ⇌ | Xe(g) + 6H$_2$O | 2.18 | 8 | $^{:792}$ |
| Fe | FeO$^{2−}$ $_4$ + 8 H$^+$ + 3 e$^−$ | ⇌ | Fe$^{3+}$ + 4H$_2$O | 2.2 | 3 | |
| Xe | XeF $_2$(aq) + 2 H$^+$ + 2 e$^−$ | ⇌ | Xe(g) + 2HF(aq) | 2.32 | 2 | |
| O | HO• +  H$^+$ +  e$^−$ | ⇌ | H$_2$O(l) | 2.38 | 1 | $^{:790}$ |
| Xe | H $_4$XeO $_6$(aq) + 2 H$^+$ + 2 e$^−$ | ⇌ | XeO $_3$(aq) + 3H$_2$O | 2.42 | 2 | $^{:792}$ |
| F | F $_2$(g) + 2 e$^−$ | ⇌ | 2F$^−$ | 2.87 | 2 | $^{:153}$ |
| Cm | Cm$^{4+}$ + e$^–$ | ⇌ | Cm$^{3+}$ | 3.0 | 1 | Estimated |
| F | F $_2$(g) + 2 H$^+$ + 2 e$^−$ | ⇌ | 2HF(aq) | 3.077 | 2 | |
| Tb | Tb$^{4+}$ + e$^–$ | ⇌ | Tb$^{3+}$ | 3.1 | 1 | Estimated |
| Pr | Pr$^{4+}$ + e$^–$ | ⇌ | Pr$^{3+}$ | 3.2 | 1 | Estimated |
| Kr | KrF $_2$(aq) + 2 e$^−$ | ⇌ | Kr(g) + 2F$^−$ (aq) | 3.27 | 2 | Estimated |