The below are standard electrode potentials taken at 25°C in aqueous solution.

Cathode (Reduction)	Half-Reaction Standard Potential E° (volts)
Li+(aq) + e- -> Li(s)	-3.04
Rb+ + e- -> Rb (s)	-2.98
K+(aq) + e- -> K(s)	-2.93
Cs+(aq) + e- -> Cs(s)	-2.92
Ba2+(aq) + 2e- -> Ba(s)	-2.91
Sr2+(aq) + 2e- -> Sr(s)	-2.89
Ca2+(aq) + 2e- -> Ca(s)	-2.76
Na+(aq) + e- -> Na(s)	-2.71
Mg2+(aq) + 2e- -> Mg(s)	-2.38
Al3+(aq) + 3e- -> Al(s)	-1.66
Mn2+(aq) + 2e- -> Mg(s)	-1.19
2H2O(l) + 2e- -> H2(g) + 2OH-(aq)	-0.83
Zn2+(aq) + 2e- -> Zn(s)	-0.76
Cr3+(aq) + 3e- -> Cr(s)	-0.74
Fe2+(aq) + 2e- -> Fe(s)	-0.41
Cd2+(aq) + 2e- -> Cd(s)	-0.40
Co2+(aq) + 2e- -> Co(s)	-0.28
Ni2+(aq) + 2e- -> Ni(s)	-0.23
Sn2+(aq) + 2e- -> Sn(s)	-0.14
Pb2+(aq) + 2e- -> Pb(s)	-0.13
Fe3+(aq) + 3e- -> Fe(s)	-0.04
2H+(aq) + 2e- -> H2(g)	0.00
Sn4+(aq) + 2e- -> Sn2+(aq)	0.15
Cu2+(aq) + 2e- -> Cu+(aq)	0.16
ClO4-(aq) + H2O(l) + 2e- -> ClO3-(aq) + 2OH-(aq)	0.17
AgCl(s) + e- -> Ag(s) + Cl-(aq)	0.22
Cu2+(aq) + 2e- -> Cu(s)	0.34
ClO3-(aq) + H2O(l) + 2e- -> ClO2-(aq) + 2OH-(aq)	0.35
O-(aq) + H2O(l) + 2e- -> I-(aq) + 2OH-(aq)	0.49
Cu+(aq) + e- -> Cu(s)	0.52
I2(s) + 2e- -> 2I-(aq)	0.54
ClO2-(aq) + H2O(l) + 2e- -> ClO-(aq) + 2OH-(aq)	0.59
Fe3+(aq) + e- -> Fe2+(aq)	0.77
Hg22+(aq) + 2e- -> 2Hg(l)	0.80
Ag+(aq) + e- -> Ag(s)	0.80
Hg2+(aq) + 2e- -> Hg(l)	0.85
ClO-(aq) + H2O(l) + 2e- -> Cl-(aq) + 2OH-(aq)	0.90
2Hg2+(aq) + 2e- -> Hg22+(aq)	0.90
NO3-(aq) + 4H+(aq) + 3e- -> NO(g) + 2H2O(l)	0.96
Br2(l) + 2e- -> 2Br-(aq)	1.07
O2(g) + 4H+(aq) + 4e- -> 2H2O(l)	1.23
Cr2O72-(aq) + 14H+(aq) + 6e- -> 2Cr3+(aq) + 7H2O(l)	1.33
Cl2(g) + 2e- -> 2Cl-(aq)	1.36
Ce4+(aq) + e- -> Ce3+(aq)	1.44
MnO4-(aq) + 8H+(aq) + 5e- -> Mn2+(aq) + 4H2O(l)	1.49
H2O2(aq) + 2H+(aq) + 2e- -> 2H2O(l)	1.78
Co3+(aq) + e- -> Co2+(aq)	1.82
S2O82-(aq) + 2e- -> 2SO42-(aq)	2.01
O3(g) + 2H+(aq) + 2e- -> O2(g) + H2O(l)	2.07
F2(g) + 2e- -> 2F-(aq)	2.87

See also: electrochemical potential