Standard Reduction Potentials
45 half-reactions with E° values at 25°C. Use the calculator to find cell potentials.
| Half-Reaction (Reduction) | E° (V) | Type |
|---|---|---|
| F₂ + 2e⁻ → 2F⁻ | +2.870 | halogen |
| O₃ + 2H⁺ + 2e⁻ → O₂ + H₂O | +2.076 | nonmetal |
| S₂O₈²⁻ + 2e⁻ → 2SO₄²⁻ | +2.010 | nonmetal |
| H₂O₂ + 2H⁺ + 2e⁻ → 2H₂O | +1.776 | nonmetal |
| MnO₄⁻ + 8H⁺ + 5e⁻ → Mn²⁺ + 4H₂O | +1.510 | transition |
| Au³⁺ + 3e⁻ → Au | +1.500 | transition |
| PbO₂ + 4H⁺ + SO₄²⁻ + 2e⁻ → PbSO₄ + 2H₂O | +1.685 | post-transition |
| Cl₂ + 2e⁻ → 2Cl⁻ | +1.358 | halogen |
| Cr₂O₇²⁻ + 14H⁺ + 6e⁻ → 2Cr³⁺ + 7H₂O | +1.330 | transition |
| O₂ + 4H⁺ + 4e⁻ → 2H₂O | +1.229 | nonmetal |
| Br₂ + 2e⁻ → 2Br⁻ | +1.066 | halogen |
| NO₃⁻ + 4H⁺ + 3e⁻ → NO + 2H₂O | +0.957 | nonmetal |
| Ag⁺ + e⁻ → Ag | +0.800 | transition |
| Hg²²⁺ + 2e⁻ → 2Hg | +0.789 | transition |
| Fe³⁺ + e⁻ → Fe²⁺ | +0.771 | transition |
| MnO₄⁻ + 2H₂O + 3e⁻ → MnO₂ + 4OH⁻ | +0.595 | transition |
| I₂ + 2e⁻ → 2I⁻ | +0.536 | halogen |
| Cu⁺ + e⁻ → Cu | +0.521 | transition |
| O₂ + 2H₂O + 4e⁻ → 4OH⁻ | +0.401 | nonmetal |
| Cu²⁺ + 2e⁻ → Cu | +0.342 | transition |
| AgCl + e⁻ → Ag + Cl⁻ | +0.222 | transition |
| SO₄²⁻ + 4H⁺ + 2e⁻ → SO₂ + 2H₂O | +0.172 | nonmetal |
| Cu²⁺ + e⁻ → Cu⁺ | +0.153 | transition |
| Sn⁴⁺ + 2e⁻ → Sn²⁺ | +0.151 | post-transition |
| S + 2H⁺ + 2e⁻ → H₂S | +0.142 | nonmetal |
| 2H⁺ + 2e⁻ → H₂ | 0.000 | reference |
| Pb²⁺ + 2e⁻ → Pb | -0.126 | post-transition |
| Sn²⁺ + 2e⁻ → Sn | -0.138 | post-transition |
| Ni²⁺ + 2e⁻ → Ni | -0.257 | transition |
| Co²⁺ + 2e⁻ → Co | -0.280 | transition |
| PbSO₄ + 2e⁻ → Pb + SO₄²⁻ | -0.356 | post-transition |
| Cd²⁺ + 2e⁻ → Cd | -0.403 | transition |
| Fe²⁺ + 2e⁻ → Fe | -0.447 | transition |
| Cr³⁺ + 3e⁻ → Cr | -0.744 | transition |
| Zn²⁺ + 2e⁻ → Zn | -0.762 | transition |
| 2H₂O + 2e⁻ → H₂ + 2OH⁻ | -0.828 | nonmetal |
| Mn²⁺ + 2e⁻ → Mn | -1.185 | transition |
| Al³⁺ + 3e⁻ → Al | -1.662 | post-transition |
| Be²⁺ + 2e⁻ → Be | -1.847 | alkaline-earth |
| Mg²⁺ + 2e⁻ → Mg | -2.372 | alkaline-earth |
| Na⁺ + e⁻ → Na | -2.714 | alkali |
| Ca²⁺ + 2e⁻ → Ca | -2.868 | alkaline-earth |
| Ba²⁺ + 2e⁻ → Ba | -2.912 | alkaline-earth |
| K⁺ + e⁻ → K | -2.931 | alkali |
| Li⁺ + e⁻ → Li | -3.040 | alkali |
Sorted by E° (most positive = strongest oxidizing agent at top). The SHE (H⁺/H₂) reference is highlighted.