Standard electrode potential (data page)

The data values of standard electrode potentials (E°) are given in the table below, in volts relative to the standard hydrogen electrode, and are for the following conditions:

• A temperature of 298.15 K (25.00 °C; 77.00 °F).
• An effective concentration of 1 mol/L for each aqueous species or a species in mercury amalgam (an alloy of mercury with another metal).
• A partial pressure of 101.325 kPa (absolute) (1 atm, 1.01325 bar) for each gaseous reagent. This pressure is used because most literature data are still given for this value (1 atm) rather than for the current standard of 100 kPa (1 bar) presently considered in the standard state.
• An activity of unity for each pure solid, pure liquid, or for water (solvent). The relation in electrode potential of metals in saltwater (as electrolyte) is given in the galvanic series.
• Although many of the half cells are written for multiple-electron transfers, the tabulated potentials are for a single-electron transfer. All of the reactions should be divided by the stoichiometric coefficient for the electron to get the corresponding corrected reaction equation. For example, the equation Fe²⁺ + 2 e⁻ ⇌ Fe(s) (–0.44 V) means that it requires 2 × 0.44 eV = 0.88 eV of energy to be absorbed (hence the minus sign) in order to create one neutral atom of Fe(s) from one Fe²⁺ ion and two electrons, or 0.44 eV per electron, which is 0.44 J/C of electrons, which is 0.44 V.
• After dividing by the number of electrons, the standard potential E° is related to the standard Gibbs free energy of formation ΔG_f° by:
  $${\displaystyle E={\frac {\sum \Delta G_{\text{left}-\sum \Delta G_{\text{right}{F}$$

  
  where F is the Faraday constant. For example, in the equation Fe²⁺ + 2 e⁻ ⇌ Fe(s) (–0.44 V), the Gibbs energy required to create one neutral atom of Fe(s) from one Fe²⁺ ion and two electrons is 2 × 0.44 eV = 0.88 eV, or 84 895 J/mol of electrons, which is just the Gibbs energy of formation of an Fe²⁺ ion, since the energies of formation of  e⁻ and Fe(s) are both zero.

The Nernst equation will then give potentials at concentrations, pressures, and temperatures other than standard.

• Note that the table may lack consistency due to data from different sources. For example:

Cu+	+  e−	⇌	Cu(s)	(E 1 = +0.520 V)
Cu2+	+ 2 e−	⇌	Cu(s)	(E 2 = +0.337 V)
Cu2+	+  e−	⇌	Cu+	(E 3 = +0.159 V)

Calculating the potential using Gibbs free energy (E
₃ = 2E
₂ – E
₁) gives the potential for E
₃ as 0.154 V, not the experimental value of 0.159 V.

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° / V	Electrons	Ref.
	Oxidant	⇌	Reductant
Sr	Sr+ +  e−	⇌	Sr(s)	-4.101	1	[1]
Ca	Ca+ +  e−	⇌	Ca(s)	-3.8	1	[1]
Th	Th4+ +  e−	⇌	Th3+	-3.6	1	[2]
Pr	Pr3+ +  e−	⇌	Pr2+	-3.1	1	Estimated[3]
N	3N 2(g) + 2 H+ + 2 e−	⇌	2HN 3(aq)	-3.09	2	[4][5]
Li	Li+ +  e−	⇌	Li(s)	-3.0401	1	[5][6]: 153
N	N 2(g) + 4H2O + 2 e−	⇌	2NH 2OH(aq) + 2 OH−	-3.04	2	[4]
Cs	Cs+ +  e−	⇌	Cs(s)	-3.026	1	[5]
Ca	Ca(OH) 2 + 2 e−	⇌	Ca(s) + 2 OH−	-3.02	2	[1]
Er	Er3+ +  e−	⇌	Er2+	-3	1	[1]
Ba	Ba(OH) 2 + 2 e−	⇌	Ba(s) + 2 OH−	-2.99	2	[1]
Rb	Rb+ +  e−	⇌	Rb(s)	-2.98	1	[5]
K	K+ +  e−	⇌	K(s)	-2.931	1	[5]
Ba	Ba2+ + 2 e−	⇌	Ba(s)	-2.912	2	[5]
La	La(OH) 3(s) + 3 e−	⇌	La(s) + 3 OH−	-2.9	3	[5]
Fr	Fr+ +  e−	⇌	Fr(s)	-2.9	1	[1]
Sr	Sr2+ + 2 e−	⇌	Sr(s)	-2.899	2	[5]
Sr	Sr(OH) 2 + 2 e−	⇌	Sr(s) + 2 OH−	-2.88	2	[1]
Ca	Ca2+ + 2 e−	⇌	Ca(s)	-2.868	2	[5][6]: 153
Li	Li+ + C 6(s) +  e−	⇌	LiC 6(s)	-2.84	1	[5]
Eu	Eu2+ + 2 e−	⇌	Eu(s)	-2.812	2	[5]
Ra	Ra2+ + 2 e−	⇌	Ra(s)	-2.8	2	[5]
Ho	Ho3+ +  e−	⇌	Ho2+	-2.8	1	[1]
Bk	Bk3+ +  e−	⇌	Bk2+	-2.8	1	[1]
Yb	Yb2+ + 2 e−	⇌	Yb(s)	-2.76	2	[1]
Na	Na+ +  e−	⇌	Na(s)	-2.71	1	[5][7]
Mg	Mg+ +  e−	⇌	Mg(s)	-2.7	1	[1]
Nd	Nd3+ +  e−	⇌	Nd2+	-2.7	1	[1]
Mg	Mg(OH) 2 + 2 e−	⇌	Mg(s) + 2 OH−	-2.69	2	[1]
Sm	Sm2+ + 2 e−	⇌	Sm(s)	-2.68	2	[1]
Be	Be 2O2− 3 + 3H2O + 4 e−	⇌	2Be(s) + 6 OH−	-2.63	4	[1]
Pm	Pm3+ +  e−	⇌	Pm2+	-2.6	1	[1]
Dy	Dy3+ +  e−	⇌	Dy2+	-2.6	1	[1]
No	No2+ + 2 e−	⇌	No	-2.5	2	[1]
Hf	HfO(OH) 2 + H2O + 4 e−	⇌	Hf(s) + 4 OH−	-2.5	4	[1]
Th	Th(OH) 4 + 4 e−	⇌	Th(s) + 4 OH−	-2.48	4	[1]
Md	Md2+ + 2 e−	⇌	Md	-2.4	2	[1]
Tm	Tm2+ + 2 e−	⇌	Tm(s)	-2.4	2	[1]
La	La3+ + 3 e−	⇌	La(s)	-2.379	3	[5]
Y	Y3+ + 3 e−	⇌	Y(s)	-2.372	3	[5]
Mg	Mg2+ + 2 e−	⇌	Mg(s)	-2.372	2	[5]
Sc	ScF3(aq) + 3 H+ + 3 e−	⇌	Sc(s) + 3HF(aq)	-2.37	3	[6]: 792
Zr	ZrO(OH) 2(s) + H2O + 4 e−	⇌	Zr(s) + 4 OH−	-2.36	4	[5]
Pr	Pr3+ + 3 e−	⇌	Pr(s)	-2.353	3	[1]
Ce	Ce3+ + 3 e−	⇌	Ce(s)	-2.336	3	[1]
Er	Er3+ + 3 e−	⇌	Er(s)	-2.331	3	[1]
Ho	Ho3+ + 3 e−	⇌	Ho(s)	-2.33	3	[1]
Al	H 2AlO− 3 + H2O + 3 e−	⇌	Al(s) + 4 OH−	-2.33	3	[1]
Nd	Nd3+ + 3 e−	⇌	Nd(s)	-2.323	3	[1]
Tm	Tm3+ + 3 e−	⇌	Tm(s)	-2.319	3	[1]
Al	Al(OH) 3(s) + 3 e−	⇌	Al(s) + 3 OH−	-2.31	3	[8]
Sm	Sm3+ + 3 e−	⇌	Sm(s)	-2.304	3	[1]
Fm	Fm2+ + 2 e−	⇌	Fm	-2.3	2	[1]
Am	Am3+ +  e−	⇌	Am2+	-2.3	1	[1]
Dy	Dy3+ + 3 e−	⇌	Dy(s)	-2.295	3	[1]
Lu	Lu3+ + 3 e−	⇌	Lu(s)	-2.28	3	[1]
Sc	ScF+ 2 + 2 H+ + 3 e−	⇌	Sc(s) + 2HF(l)	-2.28	3	[6]: 792
Tb	Tb3+ + 3 e−	⇌	Tb(s)	-2.28	3	[1]
Gd	Gd3+ + 3 e−	⇌	Gd(s)	-2.279	3	[1]
H	H 2(g) + 2 e−	⇌	2H−	-2.23	2	[1]
Es	Es2+ + 2 e−	⇌	Es(s)	-2.23	2	[1]
Pm	Pm2+ + 2 e−	⇌	Pm(s)	-2.2	2	[1]
Tm	Tm3+ +  e−	⇌	Tm2+	-2.2	1	[1]
Dy	Dy2+ + 2 e−	⇌	Dy(s)	-2.2	2	[1]
Ac	Ac3+ + 3 e−	⇌	Ac(s)	-2.2	3	[1]
Yb	Yb3+ + 3 e−	⇌	Yb(s)	-2.19	3	[1]
Cf	Cf2+ + 2 e−	⇌	Cf(s)	-2.12	2	[1]
Nd	Nd2+ + 2 e−	⇌	Nd(s)	-2.1	2	[1]
Ho	Ho2+ + 2 e−	⇌	Ho(s)	-2.1	2	[1]
Sc	Sc3+ + 3 e−	⇌	Sc(s)	-2.077	3	[9]
Al	AlF3−6 + 3 e−	⇌	Al(s) + 6F−	-2.069	3	[1]
Am	Am3+ + 3 e−	⇌	Am(s)	-2.048	3	[1]
Cm	Cm3+ + 3 e−	⇌	Cm(s)	-2.04	3	[1]
Pu	Pu3+ + 3 e−	⇌	Pu(s)	-2.031	3	[1]
Pr	Pr2+ + 2 e−	⇌	Pr(s)	-2	2	[1]
Er	Er2+ + 2 e−	⇌	Er(s)	-2	2	[1]
Eu	Eu3+ + 3 e−	⇌	Eu(s)	-1.991	3	[1]
Lr	Lr3+ + 3 e−	⇌	Lr	-1.96	3	[1]
Cf	Cf3+ + 3 e−	⇌	Cf(s)	-1.94	3	[1]
Es	Es3+ + 3 e−	⇌	Es(s)	-1.91	3	[1]
Pa	Pa4+ +  e−	⇌	Pa3+	-1.9	1	[1]
Am	Am2+ + 2 e−	⇌	Am(s)	-1.9	2	[1]
Th	Th4+ + 4 e−	⇌	Th(s)	-1.899	4	[1]
Fm	Fm3+ + 3 e−	⇌	Fm	-1.89	3	[1]
N	N2(g) + 2H2O(l) + 4 H+ + 2 e−	⇌	2NH3OH+	-1.87	2	[6]: 789
Np	Np3+ + 3 e−	⇌	Np(s)	-1.856	3	[1]
Be	Be2+ + 2 e−	⇌	Be(s)	-1.847	2	[1]
P	H 2PO− 2 +  e−	⇌	P(s) + 2 OH−	-1.82	1	[1]
U	U3+ + 3 e−	⇌	U(s)	-1.798	3	[1]
Sr	Sr2+ + 2 e−	⇌	Sr(Hg)	-1.793	2	[1]
B	H 2BO− 3 + H2O + 3 e−	⇌	B(s) + 4 OH−	-1.79	3	[1]
Th	ThO 2 + 4 H+ + 4 e−	⇌	Th(s) + 2H2O	-1.789	4	[1]
Hf	HfO2+ + 2 H+ + 4 e−	⇌	Hf(s) + H2O	-1.724	4	[1]
P	HPO2− 3 + 2H2O + 3 e−	⇌	P(s) + 5 OH−	-1.71	3	[1]
Si	SiO2− 3 + 3H2O + 4 e−	⇌	Si(s) + 6 OH−	-1.697	4	[1]
Al	Al3+ + 3 e−	⇌	Al(s)	-1.662	3	[1]
Ti	Ti2+ + 2 e−	⇌	Ti(s)	-1.63	2	[7]
Zr	ZrO 2(s) + 4 H+ + 4 e−	⇌	Zr(s) + 2H2O	-1.553	4	[10]
Zr	Zr4+ + 4 e−	⇌	Zr(s)	-1.45	4	[10]
Ti	Ti3+ + 3 e−	⇌	Ti(s)	-1.37	3	[11]
Ti	TiO(s) + 2 H+ + 2 e−	⇌	Ti(s) + H2O	-1.31	2	[6]: 792
B	B(OH)− 4 + 4H2O(l) + 8 e−	⇌	BH− 4 + 8OH−	-1.24	8	[6]: 788
Ga	GaO(OH)− 2 + H2O(l) + 3 e−	⇌	Ga(s) + 3OH−	-1.22	3	[6]: 788
Ti	Ti 2O 3(s) + 2 H+ + 2 e−	⇌	2TiO(s) + H2O	-1.23	2	[6]: 792
Zn	Zn(OH)2− 4 + 2 e−	⇌	Zn(s) + 4 OH−	-1.199	2	[10]
Mn	Mn2+ + 2 e−	⇌	Mn(s)	-1.185	2	[10]
Fe	Fe(CN)4− 6 + 6 H+ + 2 e−	⇌	Fe(s) + 6HCN(aq)	-1.16	2	[12]
C	C(s) + 3H2O(l) + 2 e−	⇌	CH3OH(l) + 2OH−	-1.148	2	[6]: 788
Cr	Cr(CN)3− 6 +  e−	⇌	Cr(CN)4− 6	-1.143	1	[6]: 793
Te	Te(s) + 2 e−	⇌	Te2−	-1.143	2	[13]
V	V2+ + 2 e−	⇌	V(s)	-1.13	2	[13]
Nb	Nb3+ + 3 e−	⇌	Nb(s)	-1.099	3	[8]
Sn	Sn(s) + 4 H+ + 4 e−	⇌	SnH 4(g)	-1.07	4
Cr	[Cr( edta)(H 2O)]− +  e−	⇌	[Cr( edta)(H 2O)]2−	-0.99	1	[6]: 793
P	2H3PO4(aq) + 2 H+ + 2 e−	⇌	(H2PO3)2(aq) + H2O(l)	-0.933	2	[6]: 789
C	CO2− 3 + 3 H+ + 2 e−	⇌	HCO− 2 + H2O(l)	-0.93	2	[6]: 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	[6]: 788
Cr	Cr2+ + 2 e−	⇌	Cr(s)	-0.9	2	[6]: 793
B	B(OH) 3(aq) + 3 H+ + 3 e−	⇌	B(s) + 3H2O	-0.89	3	[6]: 788
Fe	Fe(OH) 2(s) + 2 e−	⇌	Fe(s) + 2 OH−	-0.89	2	[12]
Fe	Fe 2O 3(s) + 3H2O + 2 e−	⇌	2Fe(OH) 2(s) + 2 OH−	-0.86	2	[12]
H	2H2O + 2 e−	⇌	H 2(g) + 2 OH−	-0.8277	2	[10]
Bi	Bi(s) + 3 H+ + 3 e−	⇌	BiH 3	-0.8	3	[10]
Zn	Zn2+ + 2 e−	⇌	Zn(Hg)	-0.7628	2	[10]
Zn	Zn2+ + 2 e−	⇌	Zn(s)	-0.7618	2	[10]
Ta	Ta 2O 5(s) + 10 H+ + 10 e−	⇌	2Ta(s) + 5H2O	-0.75	10
Cr	Cr3+ + 3 e−	⇌	Cr(s)	-0.744	3	[8]
Te	2Te(s) + 2 e−	⇌	Te2− 2	-0.74	2	[6]: 790
Ni	Ni(OH) 2(s) + 2 e−	⇌	Ni(s) + 2 OH−	-0.72	2	[1]
Nb	Nb2O5(s) + 10 H+ + 10 e−	⇌	2Nb(s) + 5H2O(l)	-0.7	10	[6]: 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	[6]: 790
Sb	Sb(OH)− 4 + 3 e−	⇌	Sb(s) + 4OH−	-0.639	3	[6]: 789
Au	[Au(CN) 2]− +  e−	⇌	Au(s) + 2CN−	-0.6	1
Ta	Ta3+ + 3 e−	⇌	Ta(s)	-0.6	3	[8]
Pb	PbO(s) + H2O + 2 e−	⇌	Pb(s) + 2 OH−	-0.580	2	[8]
Ti	2TiO 2(s) + 2 H+ + 2 e−	⇌	Ti 2O 3(s) + H2O	-0.56	2	[6]: 792
Ga	Ga3+ + 3 e−	⇌	Ga(s)	-0.549	3	[8]
U	U4+ +  e−	⇌	U3+	-0.52	1	[14]
Sb	Sb + 3 e−	⇌	SbH 3	-0.51	3	[6]: 789
P	H 3PO 2(aq) +  H+ +  e−	⇌	P(white)[note 1] + 2H2O	-0.508	1	[10]
P	H 3PO 3(aq) + 2 H+ + 2 e−	⇌	H 3PO 2(aq) + H2O	-0.499	2	[10]
Ni	NiO 2(s) + 2H2O + 2 e−	⇌	Ni(OH) 2(s) + 2 OH−	-0.49	2	[1]
Sb	Sb(OH)− 6 + 2 e−	⇌	Sb(OH)− 4 + 2OH−	-0.465	2	[6]: 789
P	H 3PO 3(aq) + 3 H+ + 3 e−	⇌	P(red)[note 1] + 3H2O	-0.454	3	[10]
Bi	Bi2O3(s) + 3H2O(l) + 6 e−	⇌	Bi(s) + 6OH−	-0.452	6	[6]: 789
Ta	TaF2− 7 + 7 H+ + 5 e−	⇌	Ta(s) + 7HF(l)	-0.45	5	[6]: 793
In	In3+ + 2 e−	⇌	In+	-0.444	2	[6]: 788
Cu	Cu(CN)− 2 +  e−	⇌	Cu(s) + 2CN−	-0.44	1	[13]
Fe	Fe2+ + 2 e−	⇌	Fe(s)	-0.44	2	[7]
C	2CO 2(g) + 2 H+ + 2 e−	⇌	HOOCCOOH(aq)	-0.43	2
Cr	Cr3+ +  e−	⇌	Cr2+	-0.407	1	[8]
Cd	Cd2+ + 2 e−	⇌	Cd(s)	-0.4	2	[7]
Ti	Ti3+ +  e−	⇌	Ti2+	-0.37	1	[6]: 792
Cu	Cu 2O(s) + H2O + 2 e−	⇌	2Cu(s) + 2 OH−	-0.36	2	[10]
Pb	PbSO 4(s) + 2 e−	⇌	Pb(s) + SO2− 4	-0.3588	2	[10]
Pb	PbSO 4(s) + 2 e−	⇌	Pb(Hg) + SO2− 4	-0.3505	2	[10]
Eu	Eu3+ +  e−	⇌	Eu2+	-0.35	1	[14]
In	In3+ + 3 e−	⇌	In(s)	-0.34	3	[13]
Tl	Tl+ +  e−	⇌	Tl(s)	-0.34	1	[13]
Ge	Ge(s) + 4 H+ + 4 e−	⇌	GeH 4(g)	-0.29	4
Co	Co2+ + 2 e−	⇌	Co(s)	-0.28	2	[10]
P	H 3PO 4(aq) + 2 H+ + 2 e−	⇌	H 3PO 3(aq) + H2O	-0.276	2	[10]
N	N2(g) + 8 H+ + 6 e−	⇌	2NH+ 4	-0.27	6	[15]
V	V3+ +  e−	⇌	V2+	-0.26	1	[7]
Ni	Ni2+ + 2 e−	⇌	Ni(s)	-0.257	2	[8]
S	2HSO− 4 + 2 H+ + 2 e−	⇌	S2O2− 6 + 2H2O(l)	-0.253	2	[6]: 790
As	As(s) + 3 H+ + 3 e−	⇌	AsH 3(g)	-0.23	3	[13]
N	N2(g) + 5 H+ + 4 e−	⇌	N2H+ 5	-0.23	4	[6]: 789
Ga	Ga+ +  e−	⇌	Ga(s)	-0.2	1	[8]
Ag	AgI(s) +  e−	⇌	Ag(s) + I−	-0.15224	1	[10]
Ge	GeO2(s) + 4 H+ + 4 e−	⇌	Ge(s) + H2O(l)	-0.15	4	[15]
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	[6]: 788
Pb	Pb2+ + 2 e−	⇌	Pb(s)	-0.126	2	[7]
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	[8]
P	P(red) + 3 H+ + 3 e−	⇌	PH 3(g)	-0.111	3	[10]
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	[6]: 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	[6]: 788
Cu	Cu(NH 3)+ 2 +  e−	⇌	Cu(s) + 2NH 3(aq)	-0.1	1	[13]
Nb	Nb2O5(s) + 10 H+ + 4 e−	⇌	2Nb3+ + 5H2O(l)	-0.1	4	[6]: 793
W	WO 3(aq) + 6 H+ + 6 e−	⇌	W(s) + 3H2O	-0.09	6	[13]
Sn	SnO 2(s) + 2 H+ + 2 e−	⇌	α-SnO(s) + H2O	-0.088	2	[6]: 788
Fe	Fe 3O 4(s) + 8 H+ + 8 e−	⇌	3Fe(s) + 4H2O	-0.085	8	[16]
V	VOH2+ +  H+ +  e−	⇌	V2+ + H2O(l)	-0.082	1	[6]: 793
P	P(white) + 3 H+ + 3 e−	⇌	PH 3(g)	-0.063	3	[10]
N	N2O(g) + H2O(l) + 6 H+ + 4 e−	⇌	2NH3OH+	-0.05	4	[6]: 789
Fe	Fe3+ + 3 e−	⇌	Fe(s)	-0.04	3	[12]
C	HCOOH(aq) + 2 H+ + 2 e−	⇌	HCHO(aq) + H2O	-0.034	2	[6]: 788
H	2 H+ + 2 e−	⇌	H 2(g)	0	2
Ag	AgBr(s) +  e−	⇌	Ag(s) + Br−	0.07133	1	[10]
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	[13]
Ru	Ru(NH 3)3+ 6 +  e−	⇌	Ru(NH 3)2+ 6	0.1	1	[14]
N	N 2H 4(aq) + 4H2O + 2 e−	⇌	2NH+ 4 + 4 OH−	0.11	2	[4]
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	[13]
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	[6]: 790
Sb	Sb2O3(s) + 6 H+ + 6 e−	⇌	2Sb(s) + 3H2O	0.15	6	[6]: 789
Sn	Sn4+ + 2 e−	⇌	Sn2+	0.151	2	[8]
S	HSO− 4 + 3 H+ + 2 e−	⇌	SO 2(aq) + 2H2O	0.158	2	[6]: 790
Cu	Cu2+ +  e−	⇌	Cu+	0.159	1	[13]
U	UO2+ 2 +  e−	⇌	UO+ 2	0.163	1	[14]
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
C	CO 2(g) + 4 H+ + 4 e−	⇌	C(s) + 2H2O	0.2	4
Fe	3Fe 2O 3(s) + 2 H+ + 2 e−	⇌	2Fe 3O 4(s) + H2O	0.22	2	[17]: p.100
Ag	AgCl(s) +  e−	⇌	Ag(s) + Cl−	0.22233	1	[10]
As	H 3AsO 3(aq) + 3 H+ + 3 e−	⇌	As(s) + 3H2O	0.24	3	[6]: 789
Ru	Ru3+ (aq) +  e−	⇌	Ru2+ (aq)	0.249	1	[18]
Pb	PbO2(s) + H2O + 2 e−	⇌	α-PbO(s) + 2OH−	0.254	2	[6]: 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	[15]
U	UO+ 2 + 4 H+ +  e−	⇌	U4+ + 2H2O	0.273	1	[14]
Re	Re3+ + 3 e−	⇌	Re(s)	0.300	3	[8]
At	At +  e−	⇌	At-	0.3	1	[19]
Bi	Bi3+ + 3 e−	⇌	Bi(s)	0.308	3	[10]
C	2HCNO + 2 H+ + 2 e−	⇌	(CN)2 + 2H2O	0.330	2	[8]
Cu	Cu2+ + 2 e−	⇌	Cu(s)	0.337	2	[13]
V	VO2+ + 2 H+ +  e−	⇌	V3+ + H2O	0.337	1	[6]: 793
Sb	Sb2O4(s) + 2 H+ + 2 e−	⇌	Sb2O3(s) + H2O(l)	0.342	2	[6]: 789
At	At+ + 2 e−	⇌	At-	0.36	2	[20]
Fe	[Fe(CN) 6]3− +  e−	⇌	[Fe(CN) 6]4−	0.3704	1	[21]
C	(CN)2 + 2 H+ + 2 e−	⇌	2HCN	0.373	2	[8]
P	(H2PO3)2(aq) + 2 H+ + 2 e−	⇌	2H3PO3	0.38	2	[6]: 789
Fe	Fc+ +  e−	⇌	Fc(s)	0.4	1	[22]
S	2SO2(aq) + 2 H+ + 2 e−	⇌	S2O2− 3 + H2O(l)	0.4	2	[6]: 790
O	O 2(g) + 2H2O + 4 e−	⇌	4 OH−(aq)	0.401	4	[7]
Mo	H 2MoO 4 + 6 H+ + 3 e−	⇌	Mo3+ + 4H2O	0.43	3
Ru	Ru2+ (aq) + 2 e−	⇌	Ru	0.455	2	[18]
V	VO(OH)+ + 2 H+ +  e−	⇌	VOH2+ + H2O(l)	0.481	1	[6]: 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	[6]: 790
S	4SO 2(aq) + 4 H+ + 8 e−	⇌	S4O4− 6 + 2H2O(l)	0.51	8	[15]
Cu	Cu+ +  e−	⇌	Cu(s)	0.52	1	[13]
C	CO(g) + 2 H+ + 2 e−	⇌	C(s) + H2O	0.52	2	[6]: 788
I	I− 3 + 2 e−	⇌	3I−	0.53	2	[7]
Te	TeO2(s) + 4 H+ + 4 e−	⇌	Te(s) + 2H2O(l)	0.53	4	[6]: 790
Cu	Cu2+ + Cl− +  e−	⇌	CuCl(s)	0.54	1	[15]
I	I 2(s) + 2 e−	⇌	2I−	0.54	2	[7]
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	[6]: 789
S	S2O2− 6 + 4 H+ + 2 e−	⇌	2H2SO3	0.569	2	[6]: 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	[1]
S	S 2O2− 3 + 6 H+ + 4 e−	⇌	2S(s) + 3H2O	0.6	4	[6]: 790
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	[15]
O	O 2(g) + 2 H+ + 2 e−	⇌	H 2O 2(aq)	0.695	2	[8]
Sb	Sb2O5(s) + 4 H+ + 4 e−	⇌	Sb2O3(s) + 2H2O	0.699	4	[6]: 789
C	+ 2 H+ + 2 e−	⇌		0.6992	2	[10]
V	H2V10O4− 28 + 24 H+ + 10 e−	⇌	10VO(OH)+ + 8H2O(l)	0.723	10	[6]: 793
Pt	PtCl2− 6 + 2 e−	⇌	PtCl2− 4 + 2Cl−	0.726	2	[14]
Fe	Fe 2O 3(s) + 6 H+ + 2 e−	⇌	2Fe2+ + 3H2O	0.728	2	[17]: p.100
Se	H 2SeO 3(aq) + 4 H+ + 4 e−	⇌	Se(s) + 3H2O	0.74	4	[8]
At	AtO+ + 2 H+ + 2 e−	⇌	At+ + H2O	0.74	2	[20]
Tl	Tl3+ + 3 e−	⇌	Tl(s)	0.741	3	[8]
No	No3+ +  e−	⇌	No2+	0.75	1	[23]
Pt	PtCl2− 4 + 2 e−	⇌	Pt(s) + 4Cl−	0.758	2	[14]
Br	BrO− + H2O(l) + 2 e−	⇌	Br− + 2OH−	0.76	2	[6]: 791
Po	Po4+ + 4 e−	⇌	Po	0.76	4	[8]
S	(SCN)2 + 2 e−	⇌	2SCN-	0.77	2	[8]
Fe	Fe3+ +  e−	⇌	Fe2+	0.771	1	[8]
Hg	Hg2+ 2 + 2 e−	⇌	2Hg(l)	0.7973	2	[8]
Ag	Ag+ +  e−	⇌	Ag(s)	0.7996	1	[10]
N	2NO− 3(aq) + 4 H+ + 2 e−	⇌	N 2O 4(g) + 2H2O	0.803	2	[6]: 789
Fe	2FeO2− 4 + 5H2O + 6 e−	⇌	Fe 2O 3(s) + 10 OH−	0.81	6	[12]
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	[6]: 153
Mn	MnO− 4 +  H+ +  e−	⇌	HMnO− 4	0.9	1
Po	Po4+ + 2 e−	⇌	Po2+	0.9	2	[8]
Hg	2Hg2+ + 2 e−	⇌	Hg2+ 2	0.91	2	[13]
Pd	Pd2+ + 2 e−	⇌	Pd(s)	0.915	2	[14]
Au	[AuCl 4]− + 3 e−	⇌	Au(s) + 4Cl−	0.93	3
N	NO− 3 + 3 H+ + 2 e−	⇌	HNO2(aq)	0.94	2	[6]: 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	[7]
Au	[AuBr 2]− +  e−	⇌	Au(s) + 2Br−	0.96	1
Fe	Fe 3O 4(s) + 8 H+ + 2 e−	⇌	3Fe2+ + 4H2O	0.98	2	[17]: p.100
Xe	[HXeO 6]3− + 2H2O + 2 e−	⇌	[HXeO 4]− + 4 OH−	0.99	2	[6]: 792 [24]
N	HNO2(aq) +  H+ +  e−	⇌	NO(g) + H2O(l)	0.996	1	[6]: 789
At	HAtO +  H+ +  e−	⇌	At + H2O	1.0	1	[19]
V	[VO 2]+ (aq) + 2 H+ +  e−	⇌	[VO]2+ (aq) + H2O	1	1	[25]
Te	H 6TeO 6(aq) + 2 H+ + 2 e−	⇌	TeO 2(s) + 4H2O	1.02	2	[25]
N	NO2(g) + 2 H+ + 2 e−	⇌	NO(g) + H2O(l)	1.03	2	[15]
Br	Br− 3 + 2 e−	⇌	3Br−	1.05	2	[15]
Sb	Sb2O5(s) + 2 H+ + 2 e−	⇌	Sb2O4(s) + H2O(l)	1.055	2	[6]: 789
I	ICl− 2 +  e−	⇌	2Cl− + I(s)	1.06	1	[15]
Br	Br 2(l) + 2 e−	⇌	2Br−	1.066	2	[10]
N	N2O4(g) + 2 H+ + 2 e−	⇌	2HNO2	1.07	2	[6]: 789
Br	Br 2(aq) + 2 e−	⇌	2Br−	1.0873	2	[10]
Ru	RuO 2 + 4 H+ + 2 e−	⇌	Ru2+ (aq) + 2H2O	1.120	2	[18]
Cu	Cu2+ + 2CN− +  e−	⇌	Cu(CN)− 2	1.12	1	[13]
I	IO− 3 + 5 H+ + 4 e−	⇌	HIO(aq) + 2H2O	1.13	4	[6]: 791
O	H2O2(aq) +  H+ +  e−	⇌	H2O(l) + HO•	1.14	1	[6]: 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	[6]: 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	[6]: 791
Xe	[HXeO 6]3− + 5H2O + 8 e−	⇌	Xe(g) + 11 OH−	1.18	8	[24]
Pt	Pt2+ + 2 e−	⇌	Pt(s)	1.188	2	[14]
Cl	ClO 2(g) +  H+ +  e−	⇌	HClO 2(aq)	1.19	1	[26]
I	2IO− 3 + 12 H+ + 10 e−	⇌	I 2(s) + 6H2O	1.2	10	[15]
Mn	MnO 2(s) + 4 H+ + 2 e−	⇌	Mn2+ + 2H2O	1.224	2	[10]
O	O 2(g) + 4 H+ + 4 e−	⇌	2H2O	1.229	4	[7]
N	N2H+ 5 + 3 H+ + 2 e−	⇌	2NH+ 4	1.28	2	[6]: 789
Cl	ClO− 4 + 2 H+ + 2 e−	⇌	ClO− 3 + H2O	1.23	2	[27]
Ru	[Ru(bipy) 3]3+ +  e−	⇌	[Ru(bipy) 3]2+	1.24	1	[1]
Xe	[HXeO 4]− + 3H2O + 6 e−	⇌	Xe(g) + 7 OH−	1.24	6	[6]: 792 [24]
N	2NO− 3 + 12 H+ + 10 e−	⇌	N2(g) + 6H2O(l)	1.25	10	[6]: 789
Tl	Tl3+ + 2 e−	⇌	Tl+	1.25	2	[6]: 788
N	2HNO2(aq) + 4 H+ + 4 e−	⇌	N2O(g) + 3H2O(l)	1.297	2	[6]: 789
Cr	Cr 2O2− 7 + 14 H+ + 6 e−	⇌	2Cr3+ + 7H2O	1.38	6	[6]: 793
N	NH3OH+ + 2 H+ + 2 e−	⇌	NH+ 4 + H2O(l)	1.35	2	[6]: 789
Cl	Cl 2(g) + 2 e−	⇌	2Cl−	1.36	2	[7]
Ru	RuO− 4(aq) + 8 H+ + 5 e−	⇌	Ru2+ (aq) + 4H2O	1.368	5	[18]
Ru	RuO 4 + 4 H+ + 4 e−	⇌	RuO 2 + 2H2O	1.387	4	[18]
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	[4]
I	2HIO(aq) + 2 H+ + 2 e−	⇌	I 2(s) + 2H2O	1.44	2	[6]: 791
Br	BrO− 3 + 5 H+ + 4 e−	⇌	HBrO(aq) + 2H2O	1.447	4	[6]: 791
Pb	β-PbO 2(s) + 4 H+ + 2 e−	⇌	Pb2+ + 2H2O	1.46	2	[13]
Pb	α-PbO 2(s) + 4 H+ + 2 e−	⇌	Pb2+ + 2H2O	1.468	2	[13]
Br	2BrO− 3 + 12 H+ + 10 e−	⇌	Br 2(l) + 6H2O	1.48	10
Cl	2ClO− 3 + 12 H+ + 10 e−	⇌	Cl 2(g) + 6H2O	1.49	10
Cl	HClO(aq) +  H+ + 2 e−	⇌	Cl− (aq) + H2O	1.49	2	[1]
At	HAtO3 + 4 H+ + 4 e−	⇌	HAtO + 2H2O	1.5	4	[19]
Mn	MnO− 4 + 8 H+ + 5 e−	⇌	Mn2+ + 4H2O	1.51	5	[15]
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	[18]
N	2NO(g) + 2 H+ + 2 e−	⇌	N2O(g) + H2O(l)	1.59	2	[6]: 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	[26]
I	IO− 4 + 2 H+ + 2 e−	⇌	IO− 3 + H2O	1.64	2	[27]
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	[26]
Pb	Pb4+ + 2 e−	⇌	Pb2+	1.69	2	[13]
Mn	MnO− 4 + 4 H+ + 3 e−	⇌	MnO 2(s) + 2H2O	1.7	3	[15]
Br	BrO− 4 + 2 H+ + 2 e−	⇌	BrO− 3 + H2O	1.74	2	[27]
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	[6]: 789
O	H 2O 2(aq) + 2 H+ + 2 e−	⇌	2H2O	1.78	2	[26]
Au	Au+ +  e−	⇌	Au(s)	1.83	1	[13]
Co	Co3+ +  e−	⇌	Co2+	1.92	1	[8]
Ag	Ag2+ +  e−	⇌	Ag+	1.98	1	[13]
O	S 2O2− 8 + 2 e−	⇌	2SO2− 4	2.01	2	[10]
O	O 3(g) + 2 H+ + 2 e−	⇌	O 2(g) + H2O	2.075	2	[14]
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	[6]: 792 [24]
Xe	H 4XeO 6(aq) + 8 H+ + 8 e−	⇌	Xe(g) + 6H2O	2.18	8	[6]: 792 [24]
Fe	FeO2− 4 + 8 H+ + 3 e−	⇌	Fe3+ + 4H2O	2.2	3	[28]
Xe	XeF 2(aq) + 2 H+ + 2 e−	⇌	Xe(g) + 2HF(aq)	2.32	2	[24][26]
O	HO• +  H+ +  e−	⇌	H2O(l)	2.38	1	[6]: 790
Xe	H 4XeO 6(aq) + 2 H+ + 2 e−	⇌	XeO 3(aq) + 3H2O	2.42	2	[24][6]: 792
F	Template:Chem(g) + 2Template:E-	⇌	2Template:Chem	2.87	2	[6]Template:Rp[7][13]
Cm	Cm4+ + e–	⇌	Cm3+	3.0	1	Estimated[3]
F	Template:Chem(g) + 2Template:H+ + 2Template:E-	⇌	2HF(aq)	3.077	2	[3]
Tb	Tb4+ + e–	⇌	Tb3+	3.1	1	Estimated[3]
Pr	Pr4+ + e–	⇌	Pr3+	3.2	1	Estimated[3]
Kr	Template:Chem(aq) + 2Template:E-	⇌	Kr(g) + 2Template:Chem(aq)	3.27	2	Estimated[29]