ELECTROCHEMICAL SERIES
Petr Vanýsek
There are three tables for this electrochemical series. Each table lists standard reduction potentials, E° values, at 298.15 K (25 °C), and at a pressure of 101.325 kPa (1 atm). Table 1 is an alphabetical listing of the elements, according to the symbol of the elements. Thus, data for silver (Ag) precede those for aluminum (Al). Table 2 lists only those reduction reactions that have E° values positive in respect to the standard hydrogen electrode. In Table 2, the reactions are listed in the order of increasing positive potential, and they range from 0.0000 V to + 3.4 V. Table 3 lists only those reduction potentials which have E° negative with respect to the standard hydrogen electrode. In Table 3, the reactions are listed in the order of decreasing potential and range from 0.0000 V to -4.10 V. The reliability of the potentials is not the same for all the data. Typically, the values with fewer significant figures have lower
reliability. The values of reduction potentials, in particular those of less common reactions, are not definite; they are subject to occasional revisions.
Abbreviations: ac = acetate; bipy = 2,2'-dipyridine, or bipyridine; en = ethylenediamine; phen = 1,10-phenanthroline.
References
1. Milazzo, G., Caroli, S., and Sharma, V. K. Tables of Standard Electrode Potentials, Wiley, Chichester, 1978.
2. Bard, A. J., Parsons, R., and Jordan, J. Standard Potentials in Aqueous Solutions, Marcel Dekker, New York, 1985.
3. Bratsch, S. G.J. Phys. Chem. Ref. Data, 18,1-21, 1989.
TABLE 1. Alphabetical Listing
Reaction	£7V	Reaction	£7V
Ac3* + 3 e ^ Ac	-2.20	As + 3 H* + 3 e ^ AsH3	-0.608
Ag+ + e ^ Ag	0.7996	As203 + 6H* + 6e^2As + 3 H20	0.234
Ag2+ + e ^ Ag+	1.980	HAs02 + 3H* + 3e^As + 2 H20	0.248
Ag(ac) + e ^ Ag + (ac)-	0.643	As02- + 2 H20 + 3e^As+4 OH-	-0.68
AgBr + e ^ Ag + Br	0.07133	H3As04 + 2H* + 2e-^ HAs02 + 2H20	0.560
AgBr03 + e^Ag + Br03-	0.546	As043- + 2 H20 + 2e^ As02- + 4OlT	-0.71
Ag2C,04 + 2e^2Ag + C,042-	0.4647	At2 + 2 e ^ 2 Ar	0.3
AgCl + e ^ Ag + Cl-	0.22233	Au* + e ^ Au	1.692
AgCN + e ^ Ag + CN-	-0.017	Au3* + 2 e ^ Au*	1.401
Ag2C03 + 2 e ^ 2 Ag + C032-	0.47	Au3* + 3 e ^ Au	1.498
Ag2Cr04 + 2 e ^ 2 Ag + CrO/-	0.4470	Au2* + e - ^ Au*	1.8
AgF + e ^ Ag + F-	0.779	AuOH2* + H* + 2 e ^ Au* + H20	1.32
Ag4[Fe(CN)J + 4 e ^ 4 Ag + [Fe(CN)6]4-	0.1478	AuBr2~ + e ^ Au + 2 Br	0.959
Agl + e ^ Ag + r	-0.15224	AuBrr + 3 e ^ Au + 4 Br	0.854
AgI03 + e ^ Ag + I03-	0.354	AuCl4- + 3 e ^ Au + 4 Cl"	1.002
Ag2Mo04 + 2 e ^ 2 Ag + Mo042-	0.4573	Au(OH)3 + 3H* + 3e^Au + 3 H20	1.45
AgN02 + e ^ Ag + 2 N02-	0.564	H2B03- + 5 H20 + 8 e ^ BH4~ + 8 OH"	-1.24
Ag20 + H20 + 2e^2Ag + 2 OH"	0.342	H2B03- + H20 + 3 e ^ B + 4 OH"	-1.79
Ag203 + H20 + 2 e ^ 2 AgO + 2 OH"	0.739	H3B03 + 3H* + 3e^B + 3 H20	-0.8698
Ag3* + 2 e ^ Ag+	1.9	B(OH)3 + 7 H* + 8 e ^ BH4~ + 3 H20	-0.481
Ag3* + e ^ Ag2+	1.8	Ba2* + 2 e ^ Ba	-2.912
Ag202 + 4 H* + e ^ 2 Ag + 2 H20	1.802	Ba2* + 2e^ Ba(Hg)	-1.570
2 AgO + H20 + 2 e ^ Ag20 + 2 OH"	0.607	Ba(OH)2 + 2 e ^ Ba + 2 OH"	-2.99
AgOCN + e ^ Ag + OCN-	0.41	Be2* + 2 e ^ Be	-1.847
Ag2S + 2 e ^ 2 Ag + S2-	-0.691	Be2032- + 3 H20 + 4e^2Be + 6 OH-	-2.63
Ag2S + 2 H+ + 2 e ^ 2 Ag + H2S	-0.0366	/)-benzoquinone + 2 H* + 2 e ^	0.6992
AgSCN + e ^ Ag + SCN-	0.08951	hydroquinone	
Ag2Se03 + 2 e ^ 2 Ag + Se042-	0.3629	Bi* + e ^ Bi	0.5
Ag2S04 + 2e^2Ag + S042-	0.654	Bi3* + 3 e ^ Bi	0.308
Ag2W04 + 2 e ^ 2 Ag + WO,2-	0.4660	Bi3* + 2 e ^ Bi*	0.2
AP+ + 3 e ^ Al	-1.662	Bi + 3 H* + 3 e ^ BiH3	-0.8
Al(OH)3 + 3 e ^ Al + 3 OH-	-2.31	BiCl4" + 3 e ^ Bi + 4 Cl"	0.16
Al(OH)4" + 3 e ^ Al + 4 OH"	-2.328	Bi203 + 3 H20 + 6e^2Bi + 6 OH-	-0.46
H2A103- + H20 + 3 e ^ Al + 4 OH-	-2.33	Bi204 + 4H* + 2e^2 BiO* + 2 H20	1.593
A1F/- + 3 e ^ Al + 6 F"	-2.069	BiO* + 2H* + 3e^Bi + H20	0.320
Am4+ + e ^ Am3*	2.60	BiOCl + 2H* + 3e^Bi + Cl~ + H20	0.1583
Am1* + 2 e ^ Am	-1.9	Bk4* + e ^ Bk3*	1.67
Am1* + 3 e ^ Am	-2.048	Bk2* + 2 e ^ Bk	-1.6
Am1* + e ^ Am2*	-2.3	Bk3* + eíí Bk2*	-2.8
5-80
Electrochemical Series
5-81
Reaction	£7V
Br2(aq) + 2 e ^ 2 Br	1.0873
Br2(l) + 2 e ^ 2 Br	1.066
HBrO + H+ + 2 e ^ Br + H20	1.331
HBrO + H+ + e ^ 1/2 Br2(aq) + H20	1.574
HBrO + H+ + e ^ 1/2 Br2(l) + H20	1.596
BrO- + H20 + 2 e ^ Br + 2 OH~	0.761
Br03- + 6 H+ + 5 e ^ 1/2 Br2 + 3 H20	1.482
Br03- + 6H+ + 6e^Br + 3 H20	1.423
Br03- + 3 H20 + 6 e ^ Br + 6 OH~	0.61
(CN)2 + 2H+ + 2e^2 HCN	0.373
2 HCNO + 2 H+ + 2 e ^ (CN)2 + 2 H20	0.330
(CNS)2 + 2 e ^ 2 CNS-	0.77
C02 + 2 H+ + 2 e ^ HCOOH	-0.199
Ca+ + e ^ Ca	-3.80
Ca2+ + 2 e ^ Ca	-2.868
Ca(OH)2 + 2 e ^ Ca + 2 OH~	-3.02
Calomel electrode, 1 molal KCl	0.2800
Calomel electrode, 1 molar KCl (NCE)	0.2801
Calomel electrode, 0.1 molar KCl	0.3337
Calomel electrode, saturated KCl (SCE)	0.2412
Calomel electrode, saturated NaCl (SSCE)	0.2360
Cd2+ + 2 e ^ Cd	-0.4030
Cd2+ + 2 e ^ Cd(Hg)	-0.3521
Cd(OH)2 + 2 e ^ Cd(Hg) + 2 OH~	-0.809
CdS04 + 2 e ^ Cd + S042-	-0.246
Cd(OH)42- + 2 e ^ Cd + 4 OH~	-0.658
CdO + H20 + 2 e ^ Cd + 2 OH~	-0.783
Ce3+ + 3 e ^ Ce	-2.336
Ce3+ + 3 e ^ Ce(Hg)	-1.4373
Ce4+ + e ^ Ce3+	1.72
CeOH3+ + H+ + e ^ Ce3+ + H20	1.715
Cf+ + e ^ CP+	3.3
CP+ + e ^ CP	-1.6
CP+ + 3 e ^ Cf	-1.94
Cf + + 2 e ^ Cf	-2.12
Cl2(g) + 2 e ^ 2 Cl-	1.35827
HCIO + H + + e ^ 1/2 Cl2 + H20	1.611
HCIO + H+ + 2 e ^ Cr + H20	1.482
CIO- + H20 + 2 e ^ Cr + 2 OH~	0.81
C102 + H+ + e ^ HC102	1.277
HC102 + 2 H+ + 2 e ^ HCIO + H20	1.645
HC102 + 3 H+ + 3 e ^ 1/2 Cl2 + 2 H20	1.628
HC102 + 3 H+ + 4 e ^ Cr + 2 H20	1.570
C102- + H20 + 2 e ^ CIO- + 2 OH~	0.66
C102- + 2 H20 + 4 e ^ Cr + 4 OH~	0.76
C102(aq) + e ^ C102-	0.954
C103- + 2 H+ + e ^ C102 + H20	1.152
C103- + 3 H+ + 2 e ^ HC102 + H20	1.214
C103- + 6 H+ + 5 e ^ 1/2 Cl2 + 3 H20	1.47
C103- + 6 H+ + 6 e ^ Cr + 3 H20	1.451
C103- + H20 + 2 e ^ C102- + 2 OH~	0.33
C103- + 3 H20 + 6 e ^ Cr + 6 OH~	0.62
C104- + 2 H+ + 2 e ^ C103- H20	1.189
C104- + 8 H+ + 7 e ^ 1/2 Cl2 + 4 H20	1.39
C104- + 8 H+ + 8 e ^ Cr + 4 H20	1.389
C104- + H20 + 2 e ^ C103- + 2 OH~	0.36
Cm4+ + e ^ Cm3*	3.0
Cm3* + 3e^ Cm	-2.04
Co2+ + 2 e ^ Co	-0.28
Co3+ + e ^ Co2+	1.92
Reaction E°l\ [Co(NH3)J3+ + e ^ [Co(NH3)J2+ 0.108
Co(OH)2 + 2 e ^ Co + 2 OH- -0.73 Co(OH)3 + e ^ Co(OH)2 + OH~ 0.17
Cr2+ + 2 e ^ Cr -0.913
Cr3+ + e ^ Cr2+ -0.407
Cr3+ + 3 e ^ Cr -0.744 Cr2072-+ 14 H++ 6 e ^ 2 Cr3++ 7 H20 1.36
Cr02- + 2H20 + 3e^Cr + 4 0H- -1.2 HCr04- + 7 H+ + 3 e ^ Cr3+ + 4 H20 1.350 Cr02 + 4 H+ + e ^ Cr3+ + 2H20 1.48 Cr(V) + e ^ Cr(IV) 1.34
Cr042- + 4 H20 + 3 e ^ Cr(OH)3 + 5 OH- -0.13
Cr(OH)3 + 3 e ^ Cr + 3 OH- -1.48
Cs+ + e ^ Cs -3.026 Cu+ + e ^ Cu 0.521 Cu2+ + e ^ Cu+ 0.153 Cu2+ + 2 e ^ Cu 0.3419 Cu2+ + 2 e ^ Cu(Hg) 0.345 Cu3+ + e ^ Cu2+ 2.4 Cu203 + 6 H+ + 2e ^ 2Cu2+ + 3 H20 2.0 Cu2+ + 2CN- + e^ [Cu(CN)J- 1.103 Cul2- + e ^ Cu + 2 I- 0.00
Cu20 + H20 + 2e^2Cu + 2 OH- -0.360
Cu(OH)2 + 2 e ^ Cu + 2 OH- -0.222
2 Cu(OH)2 + 2 e ^ Cu20 + 2 OH" + H20 -0.080
2D+ + 2e^D2 -0.013
Dy2+ + 2 e ^ Dy -2.2
Dy3* + 3 e ^ Dy -2.295
Dy3* + e ^ Dy2+ -2.6
Er2+ + 2 e ^ Er -2.0
Er3+ + 3 e ^ Er -2.331
Er3+ + e ^ Er2+ -3.0
Es3+ + e ^ Es2+ -1.3
Es3+ + 3 e ^ Es -1.91
Es2+ + 2 e ^ Es -2.23
Eu2+ + 2 e ^ Eu -2.812
Eu3+ + 3 e ^ Eu -1.991
Eu3+ + e ^ Eu2+ -0.36 F2 + 2 H+ + 2 e ^ 2 HF 3.053 F2 + 2 e ^ 2 F" 2.866 F20 + 2H+ + 4e^H20 + 2F- 2.153
Fe2+ + 2 e ^ Fe -0.447
Fe3+ + 3 e ^ Fe -0.037 Fe3+ + e ^ Fe2+ 0.771 2 HFe04- + 8 H+ + 6 e ^ Fe203 + 5 H20 2.09 HFe04- + 4 H+ + 3 e ^ FeOOH + 2 H20 2.08 HFe04- + 7 H+ + 3 e ^ Fe3+ + 4 H20 2.07 Fe203 + 4H+ + 2e^2 FeOH+ + H20 0.16 [Fe(CN)J3- + e ^ [Fe(CN)J4- 0.358 Fe042-+ 8 H++ 3 e Fe3++ 4 H20 2.20 [Fe(bipy)2]3+ + e ^ Fe(bipy)2]2+ 0.78 [Fe(bipy)3]3+ + e ^ Fe(bipy)3]2+ 1.03
Fe(OH)3 + e ^ Fe(OH)2 + OH- -0.56 [Fe(phen)3]3+ + e ^ [Fe(phen)3]2+ 1.147 [Fe(phen)3]3+ + e ^ [Fe(phen)3]2+(1 molar
H2S04) 1.06 [Ferricinium]+ + e ^ ferrocene 0.400
Fm3++ e ^ Fm2+ -1.1
Fm3+ + 3 e ^ Fm -1.89
Fm2+ + 2 e ^ Fm -2.30
5-82
Electrochemical Series
Reaction	£7V
Fr+ + e ^ Fr	-2.9
Ga3+ + 3e^ Ga	-0.549
Ga+ + e ^ Ga	-0.2
GaOH2+ + H+ + 3 e ^ Ga + H20	-0.498
H2GaO-3 + H20 + 3 e ^ Ga + 4 OH~	-1.219
Gd3+ + 3 e ^ Gd	-2.279
Ge2+ + 2 e ^ Ge	0.24
Ge4+ + 4 e ^ Ge	0.124
Ge4+ + 2 e ^ Ge2+	0.00
Ge02 + 2 H+ + 2 e ^ GeO + H20	-0.118
H2Ge03 + 4H+ + 4e^Ge + 3 H20	-0.182
2 H+ + 2 e ^ H2	0.00000
H2 + 2 e ^ 2 H"	-2.23
H02 + H+ + e^H202	1.495
2 H20 + 2 e ^ H2 + 2 OH~	-0.8277
H202 + 2H+ + 2e^2 H20	1.776
Hf+ + 4 e ^ Hf	-1.55
Hf02+ + 2H+ + 4e^Hf + H20	-1.724
Hf02 + 4H+ + 4e^Hf+2 H20	-1.505
HfO(OH)2 + H20 + 4 e ^ Hf + 4 OH~	-2.50
Hg2+ + 2 e ^ Hg	0.851
2 Hg2+ + 2 e ^ Hg22+	0.920
Hg22+ + 2 e ^ 2 Hg	0.7973
Hg2(ac)2 + 2 e ^ 2 Hg + 2(ac)"	0.51163
Hg2Br2 + 2 e ^ 2 Hg + 2 Br	0.13923
Hg2Cl2 + 2 e ^ 2 Hg + 2 Cl-	0.26808
Hg2HP04 + 2 e ^ 2 Hg + HP042~	0.6359
Hg2I2 + 2e^2Hg + 2I-	-0.0405
Hg20 + H20 + 2e^2Hg + 2 OH~	0.123
HgO + H20 + 2 e ^ Hg + 2 OH~	0.0977
Hg(OH)2 + 2H+ + 2e^Hg + 2 H20	1.034
Hg2S04 + 2e^2Hg + S042-	0.6125
Ho2+ + 2 e ^ Ho	-2.1
Ho3+ + 3 e ^ Ho	-2.33
Ho3+ + e ^ Ho2+	-2.8
I2 + 2 e ^ 21-	0.5355
I3- + 2 e ^ 3 I-	0.536
H3IOs2- + 2 e ^ IO" + 3 OH-	0.7
H5IOs + H+ + 2 e ^ I03" + 3 H20	1.601
2 HIO + 2H+ + 2e^I2 + 2 H20	1.439
HIO + H+ + 2 e ^ L + H20	0.987
IO- + H20 + 2 e ^ I- + 2 OH-	0.485
2103" + 12 H+ + 10 e ^ I2 + 6 H20	1.195
I03" + 6H+ + 6e^L + 3 H20	1.085
I03" + 2 H20 + 4 e ^ IO- + 4 OH~	0.15
I03- + 3 H20 + 6 e ^ IO- + 6 OH~	0.26
In+ + e ^ In	-0.14
In2+ + e ^ In*	-0.40
In3+ + e ^ In2+	-0.49
In3+ + 2 e ^ In+	-0.443
In3+ + 3 e ^ In	-0.3382
In(OH)3 + 3 e ^ In + 3 OH~	-0.99
In(OH)4" + 3 e ^ In + 4 OH~	-1.007
ln203 + 3 H20 + 6e^2In + 6 OH~	-1.034
Ir3+ + 3 e ^ Ir	1.156
[IrClJ2- + e ^ [IrClJ3-	0.8665
[IrClJ3- + 3 e ^ Ir + 6 Cl-	0.77
lr203 + 3 H20 + 6e^2Ir + 6 OH"	0.098
K+ + e ^ K	-2.931
La3+ + 3 e ^ La	-2.379
Reaction	£7V
La(OH)3 + 3 e ^ La + 3 OH~	-2.90
Li+ + e ^ Li	-3.0401
Lr3+ + 3 e ^ Lr	-1.96
Lu3+ + 3 e ^ Lu	-2.28
Md3+ + e ^ Md2+	-0.1
Md3+ + 3 e ^ Md	-1.65
Md2+ + 2 e ^ Md	-2.40
Mg+ + e ^ Mg	-2.70
Mg2+ + 2 e ^ Mg	-2.372
Mg(OH)2 + 2 e ^ Mg + 2 OH~	-2.690
Mn2+ + 2 e ^ Mn	-1.185
Mn3+ + e ^ Mn2+	1.5415
Mn02 + 4 H+ + 2 e ^ Mn2+ + 2 H20	1.224
Mn04- + e ^ Mn042-	0.558
Mn04- + 4 H+ + 3 e ^ Mn02 + 2 H20	1.679
Mn04- + 8 H+ + 5 e ^ Mn2+ + 4 H20	1.507
Mn04- + 2 H20 + 3 e ^ Mn02 + 4 OH~	0.595
Mn042- + 2 H20 + 2 e ^ Mn02 + 4 OH~	0.60
Mn(OH)2 + 2 e ^ Mn + 2 OH"	-1.56
Mn(OH)3 + e ^ Mn(OH)2 + OH~	0.15
Mn203 + 6 H+ + e ^ 2 Mn2+ + 3 H20	1.485
Mo3+ + 3 e ^ Mo	-0.200
Mo02 + 4H+ + 4e^Mo + 4 H20	-0.152
H3Mo70243- + 45 H+ + 42 e ^ 7 Mo + 24 H20	0.082
Mo03 + 6H+ + 6e^Mo + 3 H20	0.075
N2 + 2 H20 + 6H+ + 6e^2 NH4OH	0.092
3N2 + 2H+ + 2e^2 HN3	-3.09
Ns+ + 3 H+ + 2 e ^ 2 NH4+	1.275
N20 + 2H+ + 2e^N2 + H20	1.766
H2N202 + 2 H+ + 2 e ^ N2 + 2 H20	2.65
N204 + 2 e ^ 2 N02-	0.867
N204 + 2H+ + 2e^2 NH02	1.065
N204 + 4H+ + 4e^2NO + 2 H20	1.035
2 NH3OH+ + H+ + 2 e ^ N2H5+ + 2 H20	1.42
2NO + 2H+ + 2e^ N20 + H20	1.591
2 NO + H20 + 2 e ^ N20 + 2 OH"	0.76
HN02 + H+ + e ^ NO + H20	0.983
2 HN02 + 4 H+ + 4 e ^ H2N202 + 2 H20	0.86
2 HN02 + 4 H+ + 4 e ^ N20 + 3 H20	1.297
N02- + H20 + e ^ NO + 2 OH"	-0.46
2 N02- + 2 H20 + 4 e ^ N2022- + 4 OH"	-0.18
2 N02- + 3 H20 + 4 e ^ N20 + 6 OH"	0.15
N03- + 3 H+ + 2 e ^ HN02 + H20	0.934
N03- + 4H+ + 3e^NO + 2 H20	0.957
2 N03- + 4 H+ + 2 e ^ N204 + 2 H20	0.803
N03- + H20 + 2 e ^ N02- + 2 OH"	0.01
2 N03- + 2 H20 + 2 e ^ N204 + 4 OH"	-0.85
Na+ + e ^ Na	-2.71
Nb3+ + 3 e ^ Nb	-1.099
Nb02 + 2 H+ + 2 e ^ NbO + H20	-0.646
Nb02 + 4H+ + 4e^Nb + 2 H20	-0.690
NbO + 2H+ + 2e^Nb + H20	-0.733
Nb2Os + 10 H+ + 10 e ^ 2 Nb + 5 H20	-0.644
Nd3+ + 3 e ^ Nd	-2.323
Nd2+ + 2 e ^ Nd	-2.1
Nd3+ + e ^ Nd2+	-2.7
Ni2+ + 2 e ^ Ni	-0.257
Ni(OH)2 + 2 e ^ Ni + 2 OH~	-0.72
Ni02 + 4 H+ + 2 e ^ Ni2+ + 2 H20	1.678
NiQ2 + 2 H20 + 2 e ^ Ni(OH)2 + 2 OH~	-0.490
Electrochemical Series
5-83
Reaction	£7V	Reaction	£7V
No3+ + e ^ No2+	1.4	Pr3+ + e ^ Pr2+	-3.1
No3+ + 3 e ^ No	-1.20	Pt2+ + 2 e ^ Pt	1.18
No2+ + 2 e ^ No	-2.50	[PtCl4]2- + 2e ^ Pt + 4C1-	0.755
Np3+ + 3 e ^ Np	-1.856	[PtClJ2- + 2 e ^ [PtClJ2- + 2 Cl-	0.68
Np4+ + e ^ Np3+	0.147	Pt(OH)2 + 2 e ^ Pt + 2 OH-	0.14
Np02 + H20 + H+ + e ^ Np(OH)3	-0.962	Pt03 + 2 H+ + 2 e ^ Pt02 + H20	1.7
02 + 2H+ + 2e^H202	0.695	Pt03 + 4 H+ + 2 e ^ Pt(OH)22+ + H20	1.5
02 + 4H+ + 4e^2 H20	1.229	PtOH+ + H+ + 2 e ^ Pt + H20	1.2
02 + H20 + 2 e ^ H02- + OH"	-0.076	Pt02 + 2 H+ + 2 e ^ PtO + H20	1.01
02 + 2 H20 + 2 e ^ H202 + 2 OH"	-0.146	Pt02 + 4H+ + 4e^Pt + 2 H20	1.00
02 + 2 H20 + 4 e ^ 4 OH-	0.401	Pu3+ + 3 e ^ Pu	-2.031
03 + 2 H+ + 2 e ^ 02 + H20	2.076	Pu4+ + e ^ Pu3+	1.006
03 + H20 + 2 e ^ 02 + 2 OH"	1.24	Pu5+ + e ^ Pu4+	1.099
O(g) + 2 H+ + 2 e ^ H20	2.421	Pu02(OH)2 + 2 H+ + 2 e ^ Pu(OH)4	1.325
OH + e ^ OH-	2.02	Pu02(OH)2 + H+ + e ^ Pu02OH + H20	1.062
H02- + H20 + 2 e ^ 3 OH-	0.878	Ra2+ + 2 e ^ Ra	-2.8
Os04 + 8H+ + 8e^Os + 4 H20	0.838	Rb+ + e ^ Rb	-2.98
Os04 + 4 H+ + 4 e ^ Os02 + 2 H20	1.02	Re3+ + 3 e ^ Re	0.300
[Os(bipy)2]3+ + e ^ [Os(bipy)2]2+	0.81	Re04- + 4 H+ + 3 e ^ Re02 + 2 H20	0.510
[Os(bipy)3]3+ + e ^ [Os(bipy)3]2+	0.80	Re02 + 4H+ + 4e^Re + 2 H20	0.2513
P(red) + 3 H+ + 3 e ^ PH3(g)	-0.111	Re04- + 2 H+ + e ^ Re03 + H20	0.768
P(white) + 3 H+ + 3 e ^ PH3(g)	-0.063	Re04- + 4 H20 + 7 e ^ Re + 8 OH-	-0.584
P + 3 H20 + 3 e ^ PH3(g) + 3 OH-	-0.87	Re04- + 8H+ + 7e^Re + 4 H20	0.368
H2P2- + e ^ P + 2 OH-	-1.82	Rh+ + e ^ Rh	0.600
H3P02 + H+ + e^P + 2 H20	-0.508	Rh3+ + 3 e ^ Rh	0.758
H3P03 + 2 H+ + 2 e ^ H3P02 + H20	-0.499	[RhClJ3-+ 3 e ^ Rh + 6C1-	0.431
H3P03 + 3H+ + 3e^P + 3 H20	-0.454	RhOH2+ + H+ + 3 e ^ Rh + H20	0.83
HP032- + 2 H20 + 2 e ^ H2P02- + 3 OH-	-1.65	Ru2+ + 2 e ^ Ru	0.455
HP032- + 2 H20 + 3 e ^ P + 5 OH-	-1.71	Ru3+ + e ^ Ru2+	0.2487
H3P04 + 2 H+ + 2 e ^ H3P03 + H20	-0.276	Ru02 + 4 H+ + 2 e ^ Ru2+ + 2 H20	1.120
P043- + 2 H20 + 2 e ^ HP032- + 3 OH-	-1.05	Ru04- + e ^ Ru042-	0.59
Pa3+ + 3 e ^ Pa	-1.34	Ru04 + e ^ Ru04-	1.00
Pa4+ + 4 e ^ Pa	-1.49	Ru04 + 6 H+ + 4 e ^ Ru(OH)22+ + 2 H20	1.40
Pa4+ + e ^ Pa3+	-1.9	Ru04 + 8H+ + 8e^Ru + 4 H20	1.038
Pb2+ + 2 e ^ Pb	-0.1262	[Ru(bipy)3)3+ + e- ^ [Ru(bipy)3]2+	1.24
Pb2+ + 2 e ^ Pb(Hg)	-0.1205	[Ru(H20)J3+ + e- ^ [Ru(H20)J2+	0.23
PbBr2 + 2 e ^ Pb + 2 Br	-0.284	[Ru(NH3)J3+ + e- ^ [Ru(NH3)J2+	0.10
PbCl2 + 2 e ^ Pb + 2 Cl-	-0.2675	[Ru(en)3]3+ + e - ^ [Ru(en)3]2+	0.210
PbF2 + 2 e ^ Pb + 2 F-	-0.3444	[Ru(CN)J3- + e- ^ [Ru(CN)J4-	0.86
PbHP04 + 2 e ^ Pb + HPO/-	-0.465	S + 2 e ^ S2-	-0.47627
Pbl2 + 2 e ^ Pb + 21-	-0.365	S + 2H+ + 2 e ^ H2S(aq)	0.142
PbO + H20 + 2 e ^ Pb + 2 OH-	-0.580	S + H20 + 2 e ^ SH- + OH-	-0.478
Pb02 + 4 H+ + 2 e ^ Pb2+ + 2 H20	1.455	2 S + 2 e ^ S22-	-0.42836
HPb02- + H20 + 2 e ^ Pb + 3 OH-	-0.537	S2Os2- + 4H+ + 2e^2 H2S03	0.564
Pb02 + H20 + 2 e ^ PbO + 2 OH-	0.247	S2Os2- + 2 e ^ 2 S042-	2.010
Pb02 + S042- + 4 H+ + 2 e ^ PbS04 + 2 H20	1.6913	S2Os2- + 2H+ + 2e^2 HS04-	2.123
PbS04 + 2 e ^ Pb + S042-	-0.3588	S40/- + 2e^2S2032-	0.08
PbS04 + 2 e ^ Pb(Hg) + S042-	-0.3505	2 H2S03 + H+ + 2 e ^ HS204- + 2 H20	-0.056
Pd2+ + 2 e ^ Pd	0.951	H2S03 + 4H+ + 4e^S + 3 H20	0.449
[PdCl4]2- + 2e^Pd + 4Cl-	0.591	2 S032- + 2 H20 + 2 e ^ S2042- + 4 OH-	-1.12
[PdClJ2- + 2 e ^ [PdClJ2- + 2 Cl"	1.288	2 S032- + 3 H20 + 4 e ^ S2032- + 6 OH-	-0.571
Pd(OH)2 + 2 e ^ Pd + 2 OH-	0.07	S042- + 4 H+ + 2 e ^ H2S03 + H20	0.172
Pm2+ + 2 e ^ Pm	-2.2	2 S042- + 4 H+ + 2 e ^ S2Os2- + H20	-0.22
Pm3+ + 3e^Pm	-2.30	S042- + H20 + 2 e ^ S032- + 2 OH-	-0.93
Pm3+ + e ^ Pm2+	-2.6	Sb + 3 H+ + 3 e ^ SbH3	-0.510
Po4+ + 2 e ^ Po2+	0.9	Sb203 + 6H+ + 6e^2Sb + 3 H20	0.152
Po4+ + 4 e ^ Po	0.76	Sb2Os (senarmontite) + 4 H+ + 4 e ^ Sb203 +	0.671
Pr4+ + e ^ Pr3+	3.2	2H20	
Pr2+ + 2 e ^ Pr	-2.0	Sb2Os (valentinite) + 4 H+ + 4 e ^ Sb203 + 2	0.649
Pr3+ + 3 e ^ Pr	-2.353	H20	
5-84
Electrochemical Series
Reaction	£7V
Sb2Os + 6H+ + 4e^2 SbO+ + 3 H20	0.581
SbO+ + 2H+ + 3e^Sb + 2 H20	0.212
Sb02- + 2 H20 + 3 e ^ Sb + 4 OH~	-0.66
Sb03- + H20 + 2 e ^ Sb02- + 2 OH~	-0.59
Sc3+ + 3 e ^ Sc	-2.077
Se + 2 e ^ Se2-	-0.924
Se + 2 H+ + 2 e ^ H2Se(aq)	-0.399
H2Se03 + 4H+ + 4e^Se + 3 H20	0.74
Se + 2 H+ + 2 e ^ H2Se	-0.082
Se032- + 3 H20 + 4 e ^ Se + 6 OH~	-0.366
Se042- + 4 H+ + 2 e ^ H2Se03 + H20	1.151
Se042- + H20 + 2 e ^ Se032- + 2 OH~	0.05
SiF62- + 4 e ^ Si + 6 F-	-1.24
SiO + 2 H+ + 2 e ^ Si + H20	-0.8
Si02 (quartz) + 4H+ + 4e^Si + 2 H20	0.857
Si032- + 3 H20 + 4 e ^ Si + 6 OH~	-1.697
Sm3+ + e ^ Sm2+	-1.55
Sm3+ + 3e^ Sm	-2.304
Sm2+ + 2e^ Sm	-2.68
Sn2+ + 2 e ^ Sn	-0.1375
Sn4+ + 2 e ^ Sn2+	0.151
Sn(OH)3+ + 3 H+ + 2 e ^ Sn2+ + 3 H20	0.142
Sn02 + 4 H+ + 2 e- ^ Sn2+ + 2 H20	-0.094
Sn02 + 4H+ + 4e^Sn + 2 H20	-0.117
Sn02 + 3 H+ + 2 e ^ SnOH+ + H20	-0.194
Sn02 + 2 H20 + 4 e ^ Sn + 4 OH~	-0.945
HSn02- + H20 + 2 e ^ Sn + 3 OH~	-0.909
Sn(OH)62- + 2 e ^ HSn02- + 3 OH" + H20	-0.93
Sr+ + e ^ Sr	-4.10
Sr2+ + 2 e ^ Sr	-2.899
Sr2+ + 2 e ^ Sr(Hg)	-1.793
Sr(OH)2 + 2 e ^ Sr + 2 OH~	-2.88
Ta2Os + 10 H+ + 10 e ^ 2 Ta + 5 H20	-0.750
Ta3+ + 3 e ^ Ta	-0.6
Tc2+ + 2 e ^ Tc	0.400
Tc04- + 4 H+ + 3 e ^ Tc02 + 2 H20	0.782
Tc3+ + e ^ Tc2+	0.3
Tc04- + 8H+ + 7e^Tc + 4 H20	0.472
Tb4+ + e ^ Tb3+	3.1
Tb3+ + 3 e ^ Tb	-2.28
Te + 2 e ^ Te2-	-1.143
Te + 2 H+ + 2 e ^ H/Te	-0.793
Te4+ + 4 e ^ Te	0.568
Te02 + 4H+ + 4e^Te + 2 H20	0.593
Te032- + 3 H20 + 4 e ^ Te + 6 OH~	-0.57
Te04- + 8H+ + 7e^Te + 4 H20	0.472
H6TeOs + 2 H+ + 2 e ^ Te02 + 4 H20	1.02
Th4+ + 4 e ^ Th	-1.899
Th02 + 4H+ + 4e^Th + 2 H20	-1.789
Th(OH)4 + 4 e ^ Th + 4 OH~	-2.48
Ti2+ + 2 e ^ Ti	-1.630
Ti3+ + e ^ TP	-0.9
Ti02 + 4 H+ + 2 e ^ Ti2+ + 2 H20	-0.502
Ti3+ + 3 e ^ Ti	-1.37
TiOH3+ + H+ + e ^ Ti3+ + HO	-0.055
Reaction E°l\
T1+ + e ^ Tl -0.336
T1+ + e ^ Tl(Hg) -0.3338 Tl3+ + 2e^Tl+ 1.252 Tl3+ + 3 e ^ Tl 0.741
TIBr + e ^ Tl + Br -0.658
T1C1 + e ^ Tl + CI- -0.5568
Til + e ^ Tl + I- -0.752 T1203 + 3 H20 + 4 e ^ 2 T1+ + 6 OH- 0.02
TIOH + e ^ Tl + OH- -0.34
Tl(OH)3 + 2 e ^ TIOH + 2 OH- -0.05
T12S04 + 2 e ^ Tl + S042- -0.4360
Tm3+ + e ^ Tm2+ -2.2
Tm3+ + 3 e ^ Tm -2.319
Tm2+ + 2 e ^ Tm -2.4
U3+ + 3 e ^ U -1.798
U4+ + e ^ U3+ -0.607 U02+ + 4 H+ + e ^ U4+ + 2 H20 0.612 U022+ + e ^ UO+2 0.062 U022+ + 4 H+ + 2 e ^ U4+ + 2 H20 0.327
U022+ + 4H+ + 6e^U + 2H20 -1.444
V2+ + 2e^V -1.175
V3+ + e ^ V2+ -0.255 V02+ + 2 H+ + e ^ V3+ + H20 0.337 V02+ + 2 H+ + e ^ V02+ + H20 0.991 V2Os + 6H+ + 2e^2 V02+ + 3 H20 0.957
V2Os + 10 H+ + 10 e ^ 2 V + 5 H20 -0.242 V(OH)4++ 2 H++ e ^ V02++ 3 H20 1.00
V(OH)4+ + 4H+ + 5e^V + 4 H20 -0.254 [V(phen)3]3+ + e ^ [V(phen)3]2+ 0.14 W3+ + 3 e ^ W 0.1
W2Os + 2H+ + 2e^2 W02 + H20 -0.031
W02 + 4H+ + 4e^W + 2H20 -0.119
W03 + 6H+ + 6e^W + 3 H20 -0.090 W03 + 2 H+ + 2 e ^ W02 + H20 0.036
2 W03 + 2 H+ + 2 e ^ W2Os + H20 -0.029 H4XeOs + 2 H+ + 2 e ^ Xe03 + 3 H20 2.42 Xe03 + 6H+ + 6e^Xe + 3H20 2.10 XeF + e ^ Xe + F" 3.4
Y3+ + 3 e ^ Y -2.372
Yb3+ + e ^ Yb2+ -1.05
Yb3+ + 3 e ^ Yb -2.19
Yb2+ + 2 e ^ Yb -2.76
Zn2+ + 2 e ^ Zn -0.7618
Zn2+ + 2 e ^ Zn(Hg) -0.7628
Zn022- + 2H20 + 2e^Zn + 40H- -1.215
ZnS04 ■ 7 H20 + 2 e = Zn(Hg) + S042- + 7 -0.7993
H20 (Saturated ZnS04)
ZnOH+ + H+ + 2 e ^ Zn + H20 -0.497
Zn(OH)42- + 2 e ^ Zn + 4 OH- -1.199
Zn(OH)2 + 2 e ^ Zn + 2 OH- -1.249
ZnO + H20 + 2e^Zn + 20H- -1.260
Zr02 + 4H+ + 4e^Zr + 2H20 -1.553
ZrO(OH)2 + H20 + 4 e ^ Zr + 4 OH- -2.36
Zr4* + 4 e ^ Zr -1.45
Electrochemical Series
5-85
TABLE 2. Reduction Reactions Having E° Values More Positive than That of the Standard Hydrogen Electrode
Reaction	£7V	Reaction	£7V
2 H+ + 2 e ^ H2	0.00000	Hg2Cl2 + 2 e ^ 2 Hg + 2 Cl-	0.26808
Cul2~ + e ^ Cu + 21-	0.00	Calomel electrode, 1 molal KC1	0.2800
Ge4+ + 2 e ^ Ge2+	0.00	Calomel electrode, 1 molar KC1 (NCE)	0.2801
N03- + H20 + 2 e ^ N02- + 2 OH-	0.01	At2 + 2 e ^ 2 Ar	0.3
T1203 + 3 H20 + 4 e ^ 2 T1+ + 6 OH-	0.02	Re3+ + 3 e ^ Re	0.300
Se042- + H20 + 2 e ^ Se032- + 2 OH-	0.05	Tc3+ + e ^ Tc2+	0.3
W03 + 2 H+ + 2 e ^ W02 + H20	0.036	Bi3+ + 3 e ^ Bi	0.308
U022+ + e = U02+	0.062	BiO+ + 2H+ + 3e^Bi + H20	0.320
Pd(OH)2 + 2 e ^ Pd + 2 OH-	0.07	U022+ + 4 H+ + 2 e ^ U4+ + 2 H20	0.327
AgBr + e ^ Ag + Br	0.07133	C103- + H20 + 2 e ^ C102" + 2 OH"	0.33
Mo03 + 6H+ + 6e^Mo + 3 H20	0.075	2 HCNO + 2 H+ + 2 e ^ (CN)2 + 2 H20	0.330
S4062- + 2e^2S2032-	0.08	Calomel electrode, 0.1 molar KG	0.3337
H3Mo70243- + 45 H+ + 42 e ^ 7 Mo + 24 H20	0.082	V02+ + 2 H+ + e ^ V3+ + H20	0.337
AgSCN + e ^ Ag + SCN-	0.8951	Cu2+ + 2 e ^ Cu	0.3419
N2 + 2 H20 + 6H+ + 6e^2 NH4OH	0.092	Ag20 + H20 + 2e^2Ag + 2 OH"	0.342
HgO + H20 + 2 e ^ Hg + 2 OH"	0.0977	Cu2+ + 2 e ^ Cu(Hg)	0.345
lr203 + 3 H20 + 6e^2Ir + 6 OH-	0.098	AgI03 + e ^ Ag + IO3-	0.354
2 NO + 2 e ^ N2022-	0.10	[Fe(CN)J3- + e ^ [Fe(CN)J4-	0.358
[Ru(NH3)J3+ + e ^ [Ru(NH3)J2+	0.10	C104" + H20 + 2 e ^ ClO-3 + 2 OH"	0.36
W3+ + 3 e ^ W	0.1	Ag2Se03 + 2 e ^ 2 Ag + Se032-	0.3629
[Co(NH3)J3+ + e ^ [Co(NH3)J2+	0.108	Re04- + 8H+ + 7e^Re + 4 H20	0.368
Hg20 + H20 + 2e^2Hg + 2 OH"	0.123	(CN)2 + 2H+ + 2e^2 HCN	0.373
Ge4+ + 4 e ^ Ge	0.124	[Ferricinium]+ + e ^ ferrocene	0.400
Hg2Br2 + 2e^2Hg + 2Br	0.13923	Tc2+ + 2 e ^ Tc	0.400
Pt(OH)2 + 2 e ^ Pt + 2 OH-	0.14	02 + 2 H20 + 4 e ^ 4 OH"	0.401
[V(phen)3]3+ + e ^ [V(phen)3]2+	0.14	AgOCN + e ^ Ag + OCN-	0.41
S + 2H+ + 2 e ^ H2S(aq)	0.142	[RhClJ3- + 3 e ^ Rh + 6 Cl"	0.431
Sn(OH)3+ + 3 H+ + 2 e ^ Sn2+ + 3 H20	0.142	Ag2Cr04 + 2 e ^ 2 Ag + Cr042-	0.4470
Np4+ + e ^ Np3+	0.147	H2S03 + 4H+ + 4e^S + 3 H20	0.449
Ag4[Fe(CN)6] + 4 e ^ 4 Ag + [Fe(CN)J4-	0.1478	Ru2+ + 2 e ^ Ru	0.455
I03- + 2 H20 + 4 e ^ IO- + 4 OH-	0.15	Ag2Mo04 + 2 e ^ 2 Ag + Mo042-	0.4573
Mn(OH)3 + e ^ Mn(OH)2 + OH-	0.15	Ag2C204 + 2e^2Ag + C2042-	0.4647
2 N02- + 3 H20 + 4 e ^ N20 + 6 OH-	0.15	Ag2W04 + 2 e ^ 2 Ag + WO,2-	0.4660
Sn4+ + 2 e ^ Sn2+	0.151	Ag2C03 + 2e^2Ag + C032-	0.47
Sb203 + 6H+ + 6e^2Sb + 3 H20	0.152	Tc04- + 8H+ + 7e^Tc + 4 H20	0.472
Cu2+ + e ^ Cu+	0.153	Te04- + 8H+ + 7e^Te + 4 H20	0.472
BiOCl + 2 H+ + 3 e ^ Bi + CI- + H20	0.1583	IO- + H20 + 2 e ^ I- + 2 OH"	0.485
BiCl4- + 3 e ^ Bi + 4 Cl-	0.16	Ni02 + 2 H20 + 2 e ^ Ni(OH)2 + 2 OH"	0.490
Fe203 + 4H+ + 2e^2 FeOH+ + H20	0.16	Bi+ + e ^ Bi	0.5
Co(OH)3 + e ^ Co(OH)2 + OH-	0.17	Re04- + 4 H+ + 3 e ^ Re02 + 2 H20	0.510
S042- + 4 H+ + 2 e ^ H2S03 + H20	0.172	Hg2(ac)2 + 2e^2Hg + 2(ac)-	0.51163
Bi3+ + 2 e ^ Bi+	0.2	Cu+ + e ^ Cu	0.521
[Ru(en)3]3+ + e ^ [Ru(en)3]2+	0.210	I2 + 2 e ^ 2 I-	0.5355
SbO+ + 2H+ + 3e^Sb + 2 H20	0.212	I3- + 2 e ^ 3 I-	0.536
AgCl + e ^ Ag + Cl-	0.22233	AgBr03 + e ^ Ag + Br03~	0.546
[Ru(H20)J3+ + e ^ [Ru(H20)6]2+	0.23	Mn04- + e ^ Mn04-	0.558
As203 + 6H+ + 6e^2As + 3 H20	0.234	H3As04 + 2 H+ + 2 e ^ HAs02 + 2 H20	0.560
Calomel electrode, saturated NaCl (SSCE)	0.2360	S2Os2- + 4H+ + 2e^2 H2S03	0.564
Ge2+ + 2 e ^ Ge	0.24	AgN02 + e ^ Ag + N02-	0.564
Ru3+ + e ^ Ru2+	0.24	Te4+ + 4 e ^ Te	0.568
Calomel electrode, saturated KC1	0.2412	Sb2Os + 6H+ + 4e^2 SbO+ + 3 H20	0.581
Pb02 + H20 + 2 e ^ PbO + 2 OH-	0.247	Ru04- + e ^ Ru042-	0.59
HAs02 + 3H+ + 3e^As + 2 H20	0.248	[PdClJ2- + 2e^Pd + 4Cl-	0.591
Ru3+ + e ^ Ru2+	0.2487	Te02 + 4H+ + 4e^Te + 2 H20	0.593
Re02 + 4H+ + 4e^Re + 2 H20	0.2513	Mn04- + 2 H20 + 3 e ^ Mn02 + 4 OH-	0.595
I03" + 3 H2Q + 6 e ^ I- + OH-	0.26	Rh2+ + 2 e ^ Rh	0.600
5-86
Electrochemical Series
Reaction E°l\
Rh+ + e ^ Rh 0.600
Mn042- + 2 H20 + 2 e ^ Mn02 + 4 OH" 0.60
2 AgO + H20 + 2 e ^ Ag20 + 2 OH" 0.607
BrCY + 3 H20 + 6 e ^ Br + 6 OH" 0.61
U02+ + 4 H+ + e ^ U4+ + 2 H20 0.612
Hg2S04 + 2 e ^ 2 Hg + SO/- 0.6125
C103- + 3 H20 + 6 e ^ CI- + 6 OH" 0.62
Hg2HP04 + 2 e ^ 2 Hg + HP042- 0.6359
Ag(ac) + e ^ Ag + (ac)_ 0.643
Sb2Os(valentinite) + 4 H+ + 4 e ^ Sb203 + 2 H20 0.649
Ag2S04 + 2 e ^ 2 Ag + S042- 0.654
C102" + H20 + 2 e ^ CIO- + 2 OH- 0.66 Sb2Os(senarmontite) + 4 H+ + 4 e ^ Sb2Os + 2
H20 0.671
[PtClJ2- + 2 e ^ [PtClJ2- + 2 CI- 0.68
02 + 2 H+ + 2 e ^ H202 0.695
p-benzoquinone + 2 H+ + 2 e      hydroquinone 0.6992
H3IOs2- + 2 e ^ IO3- + 3 OH- 0.7
Ag203+H20 + 2e^2AgO + 2 0H- 0.739
TP+ + 3 e ^ Tl 0.741
[PtClJ2- + 2 e ^ Pt + 4 CI- 0.755
Rh3+ + 3 e ^ Rh 0.758
C102" + 2 H20 + 4 e ^ CI- + 4 OH- 0.76
2 NO + H20 + 2 e ^ N20 + 2 OH- 0.76
Po4+ + 4 e ^ Po 0.76
BrO- + H20 + 2 e ^ Br + 2 OH- 0.761
Re04- + 2 H+ +e ^ Re03 + H20 0.768
(CNS)2 + 2 e ^ 2 CNS- 0.77
[IrClJ3" + 3 e ^ Ir + 6 CI- 0.77
Fe3+ + e ^ Fe2+ 0.771
AgF + e ^ Ag + F- 0.779
[Fe(bipy)2]3+ + e ^ [Fe(bipy)2]2+ 0.78
Tc04- + 4 H+ + 3 e ^ Tc02 + 2 H20 0.782
Hg22+ + 2 e ^ 2 Hg 0.7973
Ag+ + e ^ Ag 0.7996
[Os(bipy)3]3+ + e ^ [Os(bipy)3]2+ 0.80
2 N03- + 4 H+ + 2 e ^ N204 + 2 H20 0.803
[Os(bipy)2]3+ + e ^ [Os(bipy)2]2+ 0.81
RhOH2+ + H + 3e^Rh + H20 0.83
Os04 + 8H+ + 8e^Os + 4 H20 0.838
CIO- + H20 + 2 e ^ CI- + 2 OH- 0.841
Hg2+ + 2 e ^ Hg 0.851
AuBr4- + 3 e ^ Au + 4 Br 0.854
Si02(quartz) + 4H+ + 4e^Si + 2 H20 0.857
2 HN02 + 4 H+ + 4 e ^ H2N202 + H20 0.86
[Ru(CN)J3- + e- ^ [Ru(CN)J4- 0.86
[IrClJ2- + e ^ [IrClJ3- 0.8665
N204 + 2 e ^ 2 N02- 0.867
H02- + H20 + 2 e ^ 3 OH- 0.878
Po4+ + 2 e ^ Po2+ 0.9
2 Hg2+ + 2 e ^ Hg22+ 0.920
N03- + 3 H+ + 2 e ^ HN02 + H20 0.934
Pd2+ + 2e^Pd 0.951
C102(aq) + e ^ C102" 0.954
N03- + 4H+ + 3e^NO + 2 H20 0.957
V2Os + 6H+ + 2e^2 V02+ + 3 H20 0.957
AuBr2- + e ^ Au + 2 Br 0.959
HNO, + H+ + e ^ NO + HO 0.983
Reaction	£7V
HIO + H+ + 2 e ^ I- + H20	0.987
V02+ + 2 H+ + e ^ V02+ + H20	0.991
Pt02 + 4H+ + 4e^Pt + 2 H20	1.00
Ru04 + e ^ Ru04-	1.00
V(OH)4+ + 2 H+ + e ^ V02+ + 3 H20	1.00
AuCl4- + 3 e ^ Au + 4 Cl-	1.002
Pu4+ + e ^ Pu3+	1.006
Pt02 + 2 H+ + 2 e ^ PtO + H20	1.01
Os04 + 4 H + 4 e ^ Os02 + 2 H20	1.02
H6TeOs + 2 H+ + 2 e ^ Te02 + 4 H20	1.02
[Fe(bipy)3]3+ + e ^ [Fe(bipy)3]2+	1.03
Hg(OH)2 + 2H+ + 2e^Hg + 2 H20	1.034
N204 + 4H+ + 4e^2NO + 2 H20	1.035
Ru04 + 8H+ + 8e^Ru + 4H20	1.038
[Fe(phen)3]3+ + e ^ [Fe(phen)3]2+ (1 molar H2S04)	1.06
Pu02(OH)2 + H+ + e ^ Pu02OH + H20	1.062
N204 + 2H+ + 2e^2 HN02	1.065
Br2(l) + 2 e ^ 2Br	1.066
IO3- + 6H+ + 6e^I- + 3 H20	1.085
Br2(aq) + 2 e ^ 2Br	1.0873
Pu5+ + e ^ Pu4+	1.099
Cu2+ + 2 CN- + e ^ [Cu(CN)J-	1.103
Ru02 + 4 H+ + 2 e ^ Ru2+ + 2 H20	1.120
[Fe(phen)3]3+ + e ^ [Fe(phen)3]2+	1.147
Se042- + 4 H+ + 2 e ^ H2Se03 + H20	1.151
CIO3- + 2 H+ + e ^ C102 + H20	1.152
Ir3+ + 3 e ^ Ir	1.156
Pt2+ + 2 e ^ Pt	1.18
C104" + 2 H+ + 2 e ^ CIO3- + H20	1.189
2IO3- + 12 H+ + 10 e ^ I2 + 6 H20	1.195
PtOH+ + H+ + 2 e ^ Pt + H20	1.2
CIO3- + 3 H+ + 2 e ^ HC102 + H20	1.214
Mn02 + 4 H+ + 2 e ^ Mn2+ + 2 H20	1.224
02 + 4H+ + 4e^2 H20	1.229
03 + H20 + 2 e ^ 02 + 2 OH~	1.24
[Ru(bipy)3]3+ + e ^ [Ru(bipy)3]2+	1.24
Tl3+ + 2 e ^ T1+	1.252
N2H5+ + 3H+ + 2e^2 NH4+	1.275
C102 + H+ + e ^ HC102	1.277
[PdClJ2- + 2 e ^ [PdClJ2- + 2 Cl"	1.288
2 HN02 + 4 H+ + 4 e ^ N20 + 3 H20	1.297
AuOH2+ + H+ + 2 e ^ Air + H20	1.32
Pu02(OH)2 + 2 H" + 2 e ^ Pu(OH)4	1.325
HBrO + H+ + 2 e ^ Br + H20	1.331
Cr(V) + e ^ Cr(IV)	1.34
HCr04- + 7 H+ + 3 e ^ Cr3+ + 4 H20	1.350
Cl2(g) + 2 e ^ 2C1-	1.35827
Cr2072- + 14 H+ + 6 e ^ 2 Cr3+ + 7 H20	1.36
C104" + 8 H+ + 8 e ^ Cr + 4 H20	1.389
C104" + 8 H+ + 7 e ^ 1/2 Cl2 + 4 H20	1.39
No3+ + e ^ No2+	1.4
Ru04 + 6 H+ + 4 e ^ Ru(OH)22+ + 2 H20	1.40
Au3+ + 2 e ^ Au+	1.401
2 NH3OH+ + H+ + 2 e ^ N2H5+ + 2 H20	1.42
Br03- + 6 H+ + 6 e ^ Br + 3 H20	1.423
2 HIO + 2H+ + 2e^I2 + 2 H20	1.439
Au(OH)3 + 3 H+ + 3 e ^ Air + 3 H20	1.45
Electrochemical Series
5-87
Reaction E°l\
3I03- + 6 H+ + 6 e ^ CI- + 3 H20 1.451
Pb02 +4 H+ + 2 e ^ Pb2+ + 2 H20 1.455
C103- +6H+ +5e ^ 1/2C12 + 3H20 1.47
Cr02 + 4H+ + e^Cr3+ + 2H20 1.48
Br03- +6H+ +5e ^ l/2Br2 + 3H20 1.482
HCIO + H+ + 2 e ^ CI- + H20 1.482
Mn203 + 6H+ + e^2Mn2+ + 3H20 1.485
H02 + H+ + e ^ H202 1.495
Au3+ + 3 e ^ Au 1.498
Pt03 + 4 H+ + 2 e ^ Pt(OH)22+ + H20 1.5
Mn04- + 8H+ + 5e^Mn2+ + 4H20 1.507
Mn3+ + e ^ Mn2- 1.5415
HC102 + 3H+ + 4e^Cl- + 2H20 1.570
HBrO + H+ + e ^ 1/2 Br2(aq) + H20 1.574
2NO + 2H+ + 2e^N20 + H20 1.591
Bi204 + 4H+ + 2e^2BiO+ + 2H20 1.593
HBrO + H+ + e ^ 1/2 Br2(l) + H20 1.596
HsIOs + H+ + 2 e ^ IO3- + 3 H20 1.601
HCIO + H+ + e ^ 1/2 Cl2 + H20 1.611
HC102 + 3H+ + 3e^ 1/2C12 + 2H20 1.628
HC102 + 2 H++ 2 e ^ HCIO + H20 1.645
Bk4+ + e ^ Bk3+ 1.67
Ni02 + 4H+ + 2e^Ni2+ + 2H20 1.678
Mn04- + 4H+ + 3e^Mn02 + 2H20 1.679
Pb02 + S042- + 4 H+ + 2 e ^ PbS04 + 2 H20 1.6913
Au+ + e ^ Au 1.692
Pt03 + 2 H+ + 2 e ^ Pt02 + H20 1.7
CeOH3+ + H+ + e ^ Ce3+ + H20 1.715
Ce4+ + e ^ Ce3+ 1.72
N20 + 2 H+ + 2     N2 + H20 1.766
H202 + 2H+ + 2e^2H20 1.776
Reaction E°l\
Ag3+ + e ^ Ag2+	1.8
Au2+ + e~ ^ Au+	1.8
Ag202 + 4H+ + e^2Ag + 2 H20	1.802
Co3+ + e ^ Co2-(2 molar H2S04)	1.83
Ag3+ + 2 e ^ Ag+	1.9
Co3+ + e ^ Co2+	1.92
Ag2+ + e ^ Ag+	1.980
Cu203 + 6H+ + 2e^2 Cu2+ + 3 H20	2.0
S2Os2- + 2e^2S042-	2.010
OH + e^ OH-	2.02
HFe04- + 7 H+ + 3 e ^ Fe3+ + 4 H20	2.07
03 + 2 H+ + 2 e ^ 02 + H20	2.076
HFe04- + 4 H+ + 3 e ^ FeOOH + 2 H20	2.08
2 HFe04- + 8 H+ + 6 e ^ Fe203 + 5 H20	2.09
Xe03 + 6H+ + 6e^Xe + 3 H20	2.10
S2Os2- + 2H+ + 2e^2 HS04-	2.123
F20 + 2 H+ + 4 e ^ H20 + 2 F"	2.153
Fe042- + 8 H+ + 3 e ^ Fe3+ + 4 H20	2.20
Cu3+ + e ^ Cu2+	2.4
H4XeOs + 2 H+ + 2 e ^ Xe03 + 3 H20	2.42
O(g) + 2 H+ + 2 e ^ H20	2.421
Am4+ + e ^ Am1*	2.60
H2N202 + 2 H+ + 2 e ^ N2 + 2 H20	2.65
F2 + 2 e ^ 2 F-	2.866
Cm4+ + e ^ Cm3+	3.0
F2 + 2 H+ + 2 e ^ 2 HF	3.053
Tb4+ + e ^ Tb3+	3.1
Pr4+ + e ^ Pr3+	3.2
CP+ + e ^ CP+	3.3
XeF + e ^ Xe + F"	3.4
TABLE 3. Reduction Reactions Having E° Values More Negative than That of the Standard Hydrogen Electrode
Reaction	£7V	Reaction	£7V
2 H+ + 2 e ^ H2	0.00000	W02 + 4H+ + 4e^W + 2 H20	-0.119
2 D+ + 2 e ^ D2	-0.013	Pb2+ + 2 e ^ Pb(Hg)	-0.1205
AgCN + e ^ Ag + CN-	-0.017	Pb2+ + 2 e ^ Pb	-0.1262
2 W03 + 2 H+ + 2 e ^ W2Os + H20	-0.029	Cr042- + 4 H20 + 3 e ^ Cr(OH)3 + 5 OH"	-0.13
W2Os + 2H+ + 2e^2 W02 + H20	-0.031	Sn2- + 2 e ^ Sn	-0.1375
Ag2S + 2 H+ + 2 e ^ 2 Ag + H2S	-0.0366	In+ + e ^ In	-0.14
Fe3+ + 3 e ^ Fe	-0.037	02 + 2 H20 + 2 e ^ H202 + 2 OH"	-0.146
Hg2I2 + 2e^2Hg + 2I-	-0.0405	Mo02 + 4H+ + 4e^Mo + 4 H20	-0.152
Tl(OH)3 + 2 e ^ TIOH + 2 OH~	-0.05	Agl + e ^ Ag + I-	-0.15224
TiOH3+ + H+ + e ^ Ti3+ + H20	-0.055	2 N02- + 2 H20 + 4 e ^ N2022- + 4 OH"	-0.18
2 H2S03 + H+ + 2 e ^ HS204- + 2 H20	-0.056	H2Ge03 + 4H+ + 4e^Ge + 3 H20	-0.182
P(white) + 3 H+ + 3 e ^ PH3(g)	-0.063	Sn02 + 3 H+ + 2 e ^ SnOH+ + H20	-0.194
02 + H20 + 2 e ^ H02- + OH"	-0.076	C02 + 2 H+ + 2 e ^ HCOOH	-0.199
2 Cu(OH)2 + 2 e ^ Cu20 + 2 OH" + H20	-0.080	Mo3+ + 3 e ^ Mo	-0.200
Se + 2 H+ + 2 e ^ H2Se	-0.082	Ga+ + e ^ Ga	-0.2
W03 + 6H+ + 6e^W + 3 H20	-0.090	2 S022- + 4 H+ + 2 e ^ S2062" + H20	-0.22
Sn02 + 4 H+ + 2 e ^ Sn2+ + 2 H20	-0.094	Cu(OH)2 + 2 e ^ Cu + 2 OH"	-0.222
Md3+ + e ^ Md2+	-0.1	V2Os + 10 H+ + 10 e ^ 2 V + 5 H20	-0.242
P(red) + 3 H+ + 3 e ^ PH3(g)	-0.111	CdS04 + 2 e ^ Cd + S042-	-0.246
Sn02 + 4H+ + 4e^Sn + 2 H20	-0.117	V(OH)4+ + 4H+ + 5e^V + 4 H20	-0.254
Ge02 + 2 H+ + 2 e ^ GeO + H20	-0.118	V3+ + e ^ V2+	-0.255
5-88
Electrochemical Series
Reaction	F/V
Ni2+ + 2 e ^ Ni	-0.257
PbCl2 + 2 e ^ Pb + 2 Cl-	-0.2675
H3P04 + 2 H+ + 2 e ^ H3P03 + H20	-0.276
Co2+ + 2 e ^ Co	-0.28
PbBr2 + 2 e ^ Pb + 2 Br	-0.284
Tl* + e ^ Tl(Hg)	-0.3338
Tl* + e ^ TI	-0.336
In3+ + 3 e ^ In	-0.3382
TIOH + e ^ Tl + OH-	0.34
PbF2 + 2 e ^ Pb + 2 F-	-0.3444
PbS04 + 2 e ^ Pb(Hg) + S042-	-0.3505
Cd2+ + 2 e ^ Cd(Hg)	-0.3521
PbS04 + 2 e ^ Pb + SO/-	-0.3588
CuzO + H20 + 2e^2Cu + 2 OH~	-0.360
Eu3* + e ^ Eu2+	-0.36
Pbl2 + 2 e ^ Pb + 2 I-	-0.365
Se032- + 3 H20 + 4 e ^ Se + 6 OH~	-0.366
Se + 2 H+ + 2 e ^ H2Se(aq)	-0.399
In2+ + e ^ In+	0.40
Cd2+ + 2 e ^ Cd	-0.4030
Cr3+ + e ^ Cr2+	-0.407
2 S + 2 e ^ S22-	-0.42836
TljSO, + 2 e ^ Tl + S042-	-0.4360
In3* + 2 e ^ In+	-0.443
Fe2* + 2 e ^ Fe	-0.447
H3P03 + 3H+ + 3e^P + 3 H20	-0.454
Bi203 + 3 H20 + 6e^2Bi + 6 OH"	-0.46
N02- + H20 + e ^ NO + 2 OH	-0.46
PbHP04 + 2 e ^ Pb + HP042"	-0.465
S + 2 e ^ S2-	-0.47627
S + H20 + 2 e ^ HS- + OH"	-0.478
B(OH)3 + 7 H+ + 8 e ^ BH4" + 3 H20	-0.481
In3* + e ^ In2+	-0.49
ZnOH+ + H+ + 2 e ^ Zn + H20	-0.497
GaOH2+ + H+ + 3 e ^ Ga + H20	-0.498
H3P03 + 2 H+ + 2 e ^ H3P02 + H20	-0.499
Ti02 + 4 H+ + 2 e ^ Ti2+ + 2 H20	-0.502
H3P02 + H+ + e^P + 2 H20	-0.508
Sb + 3 H+ + 3 e ^ SbH3	-0.510
HPb02- + H20 + 2 e ^ Pb + 3 OH"	-0.537
Ga3* + 3 e ^ Ga	-0.549
T1C1 + e ^ Tl + Cl-	-0.5568
Fe(OH)3 + e ^ Fe(OH)2 + OH"	-0.56
Te032- + 3 H20 + 4 e ^ Te + 6 OH"	0.57
2 S032- + 3 H20 + 4 e ^ S2032- + 6 OH~	-0.571
PbO + H20 + 2 e ^ Pb + 2 OH"	-0.580
Re02- + 4 H20 + 7 e ^ Re + 8 OH~	-0.584
Sb03- + H20 + 2 e ^ Sb02" + 2 OH"	-0.59
Ta3+ + 3 e ^ Ta	-0.6
U4* + e ^ U3+	-0.607
As + 3 H* + 3 e ^ AsH3	-0.608
Nb2Os + 10 H+ + 10 e ^ 2 Nb + 5 H20	-0.644
Nb02 + 2 H+ + 2 e ^ NbO + H20	-0.646
Cd(OH)42- + 2 e ^ Cd + 4 OH"	-0.658
TlBr + e ^ Tl + Br	-0.658
Sb02- + 2 H20 + 3 e ^ Sb + 4 OH~	-0.66
AsO - + 2 H,0 + 3 e ^ As + 4 OH~	-0.68
Reaction £°/V
Nb02 + 4H* + 4e^Nb + 2 H20 -0.690
Ag2S + 2 e ^ 2 Ag + S2- -0.691
AsO/-+ 2 H20 + 2 e ^ As02-+ 4 OH- -0.71
Ni(OH)2 + 2 e ^ Ni + 2 OH" -0.72
Co(OH)2 + 2 e ^ Co + 2 OH- -0.73
NbO + 2H* + 2e^Nb + H20 -0.733
H2Se03 + 4H* + 4e^Se + 3 H20 -0.74
Cr3+ + 3 e ^ Cr -0.744
Ta2Os + 10 H* + 10 e ^ 2 Ta + 5 H20 -0.750
TU + e ^ Tl + I" -0.752
Zn2+ + 2 e ^ Zn -0.7618
Zn2+ + 2 e ^ Zn(Hg) -0.7628
CdO + H20 + 2 e ^ Cd + 2 OH- -0.783
Te + 2 H* + 2 e ^ H2Te -0.793
ZnS047H20 + 2 e ^ Zn(Hg) + SO/- + 7 H20 -0.7993 (Saturated ZnS04)
Bi + 3 H+ + 3 e ^ BiH3 -0.8
SiO + 2 H» + 2 e ^ Si + H20 -0.8
Cd(OH)2 + 2 e ^ Cd(Hg) + 2 OH- -0.809
2 H20 + 2 e ^ H2 + 2 OH- -0.8277
2 NO-3 + 2 H20 + 2 e ^ N204 + 4 OH- -0.85
H3B03 + 3H* + 3e^B + 3 H20 -0.8698
P + 3 H20 + 3 e ^ PH3(g) + 3 OH- -0.87
Ti3+ + e ^ Ti2* -0.9
HSn02- + H20 + 2 e ^ Sn + 3 OH- -0.909
Cr2+ + 2 e ^ Cr -0.913
Se + 2 e ^ Se2" -0.924
S042- + H20 + 2 e ^ S032- + 2 OH- -0.93
Sn(OH)62" + 2 e ^ HSn02- + 3 OH- + H20 -0.93
Sn02 + 2 H20 + 4 e ^ Sn + 4 OH- -0.945
In(OH)3 + 3 e ^ In + 3 OH- -0.99
Np02 + H20 + H* + e ^ Np(OH)3 -0.962
In(OH)4" + 3 e ^ In + 4 OH- -1.007
ln203+ 3 H20 + 6e ^ 2In +6 0H- -1.034
P043-+ 2 H20 + 2 e ^ HP032-+ 3 OH- -1.05
Yb3+ + e ^ Yb2+ -1.05
Nb3+ + 3 e =f± Nb -1.099
Fm3+ + e ^ Fm2+ -1.1
2 S032-+ 2 H20 + 2 e ^ S2042-+ 4 OH- -1.12
Te + 2 e ^ Te2" -1.143
V2+ + 2e^V -1.175
Mn2+ + 2 e ^ Mn -1.185
Zn(OH)42" + 2 e ^ Zn + 4 OH- -1.199
Cr02 + 2H20 + 3e^Cr + 4 0H- -1.2
No3+ + 3 e # No -1.20
Zn02- + 2H20 + 2e^Zn + 40H- -1.215
H2Ga03- + H20 + 3 e ^ Ga + 4 OH~ -1.219
H2B03- + 5 H20 + 8 e ^ BH4- + 8 OH- -1.24
SiF62- + 4e^Si + 6F- -1.24
Zn(OH)2 + 2 e ^ Zn + 2 OH- -1.249
ZnO + H,0 + 2 e ^ Zn + 2 OH- -1.260
Es3+ + e ^ Es2+ -1.3
Pa3+ + 3 e ^ Pa -1.34
Ti3+ + 3 e ^ Ti -1.37
Ce3+ + 3 e ^ Ce(Hg) -1.4373
U022+ + 4H+ + 6e^U + 2 H20 -1.444
Zr4+ + 4 e ^ Zr -1.45
Electrochemical Series
5-89
Reaction	£7V
Cr(OH)3 + 3 e ^ Cr + 3 OH-	-1.48
Pa4+ + 4 e ^ Pa	-1.49
Hf02 + 4 H+ + 4 e ^ Hf + 2 H20	-1.505
Hf + + 4 e ^ Hf	-1.55
Sm3+ + e ^ Sm2+	-1.55
Zr02 + 4H+ + 4e^Zr + 2 H20	-1.553
Mn(OH)2 + 2 e ^ Mn + 2 OH-	-1.56
Ba2+ + 2 e ^ Ba(Hg)	-1.570
Bk2+ + 2 e ^ Bk	-1.6
CP+ + e ^ CP	-1.6
Ti2+ + 2 e ^ Ti	-1.630
Md3+ + 3 e ^ Md	-1.65
HP032- + 2 H20 + 2 e ^ H2P02- + 3 OH"	-1.65
Al3+ + 3 e ^ Al	-1.662
Si032- + H20 + 4 e ^ Si + 6 OH"	-1.697
HP032- + 2 H20 + 3 e ^ P + 5 OH-	-1.71
Hf02+ + 2H+ + 4e^Hf + H20	-1.724
Th02 + 4H+ + 4e^Th + 2 H20	-1.789
H2B03- + H20 + 3 e ^ B + 4 OH"	-1.79
Sr2+ + 2 e ^ Sr(Hg)	-1.793
U3+ + 3 e ^ U	-1.798
H2PO-2 + e ^ P + 2 OH-	-1.82
Be2+ + 2 e ^ Be	-1.847
Np3+ + 3 e ^ Np	-1.856
Fm3+ + 3e^ Fm	-1.89
Th4+ + 4 e ^ Th	-1.899
Am2+ + 2 e ^ Am	-1.9
Pa4+ + e ^ Pa3+	-1.9
Es3+ + 3 e ^ Es	-1.91
CP* + 3 e ^ Cf	-1.94
Lr3+ + 3 e ^ Lr	-1.96
Eu3+ + 3 e ^ Eu	-1.991
Er2+ + 2 e ^ Er	-2.0
Pr2+ + 2 e ^ Pr	-2.0
Pu3+ + 3 e ^ Pu	-2.031
Cm3* + 3e^ Cm	-2.04
Am3+ + 3 e ^ Am	-2.048
A1F/- + 3 e ^ Al + 6 F-	-2.069
Sc3+ + 3 e ^ Sc	-2.077
Ho2+ + 2 e ^ Ho	-2.1
Nd2+ + 2 e ^ Nd	-2.1
CP* + 2 e ^ Cf	-2.12
Yb3+ + 3 e ^ Yb	-2.19
Ac3+ + 3 e ^ Ac	-2.20
Dy2+ + 2 e ^ Dy	-2.2
Tm3+ + e ^ Tm2+	-2.2
Pm2+ + 2 e ^ Pm	-2.2
Es2+ + 2 e ^ Es	-2.23
H2 + 2 e ^ 2 H-	-2.23
Gd3+ + 3 e ^ Gd	-2.279
Tb3+ + 3 e ^ Tb	-2.28
Lu3+ + 3 e ^ Lu	-2.28
Dy3+ + 3 e ^ Dy	-2.295
Reaction	£7V
Am3+ + e ^ Am1*	-2.3
Fm2+ + 2e^ Fm	-2.30
Pm3+ + 3e^Pm	-2.30
Sm3+ + 3e^ Sm	-2.304
Al(OH)3 + 3 e ^ Al + 3 OH-	-2.31
Tm3+ + 3 e ^ Tm	-2.319
Nd3+ + 3 e ^ Nd	-2.323
Al(OH)- + 3 e ^ Al + 4 OH-	-2.328
H2A103- + H20 + 3 e ^ Al + 4 OH"	-2.33
Ho3+ + 3 e ^ Ho	-2.33
Er3+ + 3 e ^ Er	-2.331
Ce3+ + 3 e ^ Ce	-2.336
Pr3+ + 3 e ^ Pr	-2.353
ZrO(OH)2 + H20 + 4 e ^ Zr + 4 OH"	-2.36
Mg2+ + 2 e ^ Mg	-2.372
Y3+ + 3 e ^ Y	-2.372
La3+ + 3 e ^ La	-2.379
Tm2+ + 2 e ^ Tm	-2.4
Md2+ + 2 e ^ Md	-2.40
Th(OH)4 + 4 e ^ Th + 4 OH-	-2.48
HfO(OH)2 + H20 + 4 e ^ Hf + 4 OH-	-2.50
No2+ + 2 e ^ No	-2.50
Dy3+ + e ^ Dy2+	-2.6
Pm3+ + e ^ Pm2+	-2.6
Be2032- + 3 H20 + 4e^2Be + 6 OH-	-2.63
Sm2+ + 2e^ Sm	-2.68
Mg(OH)2 + 2 e ^ Mg + 2 OH-	-2.690
Nd3+ + e ^ Nd2+	-2.7
Mg+ + e ^ Mg	-2.70
Na+ + e ^ Na	-2.71
Yb2+ + 2 e ^ Yb	-2.76
Bk3+ + e ^ Bk2+	-2.8
Ho3+ + e ^ Ho2+	-2.8
Ra2+ + 2 e ^ Ra	-2.8
Eu2+ + 2 e ^ Eu	-2.812
Ca2+ + 2 e ^ Ca	-2.868
Sr(OH)2 + 2 e ^ Sr + 2 OH-	-2.88
Sr2+ + 2 e ^ Sr	-2.899
Fr+ + e ^ Fr	-2.9
La(OH)3 + 3 e ^ La + 3 OH-	-2.90
Ba2+ + 2 e ^ Ba	-2.912
K* + e ^ K	-2.931
Rb+ + e ^ Rb	-2.98
Ba(OH)2 + 2 e ^ Ba + 2 OH-	-2.99
Er3+ + e ^ Er2+	-3.0
Ca(OH)2 + 2 e ^ Ca + 2 OH-	-3.02
Cs+ + e ^ Cs	-3.026
Li+ + e ^ Li	-3.0401
3N2 + 2H+ + 2e^2 HN3	-3.09
Pr3+ + e ^ Pr2+	-3.1
Ca+ + e ^ Ca	-3.80
Sr+ + e ^ Sr	-4.10