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) precedes
those for aluminum (Al). Table 2 lists only those reduction reactions which 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. G. Milazzo, S. Caroli, and V. K. Sharma, Tables of Standard Electrode Potentials, Wiley, Chichester, 1978.
2. A. J. Bard, R. Parsons, and J. Jordan, Standard Potentials in Aqueous Solutions, Marcel Dekker, New York, 1985.
3. S. G. Bratsch, J. Phys. Chem. Ref. Data, 18, 1—21, 1989.
TABLE 1
Alphabetical Listing
Reaction
Ac3+ + 3 e 1 Ac
Ag+ + e 1 Ag
Ag2+ + e 1 Ag+
Ag(ac) + e 1 Ag + (ac)–
AgBr + e 1 Ag + Br–
AgBrO3 + e 1 Ag + BrO3–
Ag2C2O4 + 2 e 1 2 Ag + C2O42–
AgCl + e 1 Ag + Cl–
AgCN + e 1 Ag + CN–
Ag2CO3 + 2 e 1 2 Ag + CO32–
Ag2CrO4 + 2 e 1 2 Ag + CrO42–
AgF + e 1 Ag + F–
Ag4[Fe(CN)6] + 4 e 1 4 Ag + [Fe(CN)6]4–
AgI + e 1 Ag + I–
AgIO3 + e 1 Ag + IO3–
Ag2MoO4 + 2 e 1 2 Ag + MoO42–
AgNO2 + e 1 Ag + 2 NO2–
Ag2O + H2O + 2 e 1 2 Ag + 2 OH–
Ag2O3 + H2O + 2 e 1 2 AgO + 2 OH–
Ag3+ + 2 e 1 Ag+
Ag3+ + e 1 Ag2+
Ag2O2 + 4 H+ + e 1 2 Ag + 2 H2O
2 AgO + H2O + 2 e 1 Ag2O + 2 OH–
AgOCN + e 1 Ag + OCN–
Ag2S + 2 e 1 2 Ag + S2–
Ag2S + 2 H+ + 2 e 1 2 Ag + H2S
AgSCN + e 1 Ag + SCN–
Ag2SeO3 + 2 e 1 2 Ag + SeO42–
Ag2SO4 + 2 e 1 2 Ag + SO42–
Ag2WO4 + 2 e 1 2 Ag + WO42–
Al3+ + 3 e 1 Al
Al(OH)3 + 3 e 1 Al + 3 OH–
© 2000 by CRC PRESS LLC
E°/V
–2.20
0.7996
1.980
0.643
0.07133
0.546
0.4647
0.22233
–0.017
0.47
0.4470
0.779
0.1478
–0.15224
0.354
0.4573
0.564
0.342
0.739
1.9
1.8
1.802
0.607
0.41
–0.691
–0.0366
0.08951
0.3629
0.654
0.4660
–1.662
–2.31
Reaction
Al(OH)4– + 3 e 1 Al + 4 OH–
H2AlO3– + H2O + 3 e 1 Al + 4 OH–
AlF63– + 3 e 1 Al + 6 F–
Am4+ + e 1 Am3+
Am2+ + 2 e 1 Am
Am3+ + 3 e 1 Am
Am3+ + e 1 Am2+
As + 3 H+ + 3 e 1 AsH3
As2O3 + 6 H+ + 6 e 1 2 As + 3 H2O
HAsO2 + 3 H+ + 3 e 1 As + 2 H2O
AsO2– + 2 H2O + 3 e 1 As + 4 OH–
H3AsO4 + 2 H+ + 2 e–1 HAsO2 + 2 H2O
AsO43– + 2 H2O + 2 e 1 AsO2– + 4 OH–
At2 + 2 e 1 2 At–
Au+ + e 1 Au
Au3+ + 2 e 1 Au+
Au3+ + 3 e 1 Au
Au2+ + e –1 Au+
AuOH2+ + H+ + 2 e 1 Au+ + H2O
AuBr2– + e 1 Au + 2 Br–
AuBr4– + 3 e 1 Au + 4 Br–
AuCl4– + 3 e 1 Au + 4 Cl–
Au(OH)3 + 3 H+ + 3 e 1 Au + 3 H2O
H2BO3– + 5 H2O + 8 e 1 BH4– + 8 OH–
H2BO3– + H2O + 3 e 1 B + 4 OH–
H3BO3 + 3 H+ + 3 e 1 B + 3 H2O
B(OH)3 + 7 H+ + 8 e 1 BH4– + 3 H2O
Ba2+ + 2 e 1 Ba
Ba2+ + 2 e 1 Ba(Hg)
Ba(OH)2 + 2 e 1 Ba + 2 OH–
Be2+ + 2 e 1 Be
Be2O32– + 3 H2O + 4 e 1 2 Be + 6 OH–
E°/V
–2.328
–2.33
–2.069
2.60
–1.9
–2.048
–2.3
–0.608
0.234
0.248
–0.68
0.560
–0.71
0.3
1.692
1.401
1.498
1.8
1.32
0.959
0.854
1.002
1.45
–1.24
–1.79
–0.8698
–0.481
–2.912
–1.570
–2.99
–1.847
–2.63
ELECTROCHEMICAL SERIES (continued)
TABLE 1
Alphabetical Listing (continued)
Reaction
p–benzoquinone + 2 H+ + 2 e 1 hydroquinone
Bi+ + e 1 Bi
Bi3+ + 3 e 1 Bi
Bi3+ + 2 e 1 Bi+
Bi + 3 H+ + 3 e 1 BiH3
BiCl4– + 3 e 1 Bi + 4 Cl–
Bi2O3 + 3 H2O + 6 e 1 2 Bi + 6 OH–
Bi2O4 + 4 H+ + 2 e 1 2 BiO+ + 2 H2O
BiO+ + 2 H+ + 3 e 1 Bi + H2O
BiOCl + 2 H+ + 3 e 1 Bi + Cl– + H2O
Bk4+ + e 1 Bk3+
Bk2+ + 2 e 1 Bk
Bk3+ + e 1 Bk2+
Br2(aq) + 2 e 1 2 Br–
Br2(l) + 2 e 1 2 Br–
HBrO + H+ + 2 e 1 Br– + H2O
HBrO + H+ + e 1 1/2 Br2(aq) + H2O
HBrO + H+ + e 1 1/2 Br2(l) + H2O
BrO– + H2O + 2 e 1 Br– + 2 OH–
BrO3– + 6 H+ + 5 e 1 1/2 Br2 + 3 H2O
BrO3– + 6 H+ + 6 e 1 Br– + 3 H2O
BrO3– + 3 H2O + 6 e 1 Br– + 6 OH–
(CN)2 + 2 H+ + 2 e 1 2 HCN
2 HCNO + 2 H+ + 2 e 1 (CN)2 + 2 H2O
(CNS)2 + 2 e 1 2 CNS–
CO2 + 2 H+ + 2 e 1 HCOOH
Ca+ + e 1 Ca
Ca2+ + 2 e 1 Ca
Ca(OH)2 + 2 e 1 Ca + 2 OH–
Calomel electrode, 1 molal KCl
Calomel electrode, 1 molar KCl (NCE)
Calomel electrode, 0.1 molar KCl
Calomel electrode, saturated KCl (SCE)
Calomel electrode, saturated NaCl (SSCE)
Cd2+ + 2 e 1 Cd
Cd2+ + 2 e 1 Cd(Hg)
Cd(OH)2 + 2 e 1 Cd(Hg) + 2 OH–
CdSO4 + 2 e 1 Cd + SO42–
Cd(OH)42– + 2 e 1 Cd + 4 OH–
CdO + H2O + 2 e 1 Cd + 2 OH–
Ce3+ + 3 e 1 Ce
Ce3+ + 3 e 1 Ce(Hg)
Ce4+ + e 1 Ce3+
CeOH3+ + H+ + e 1 Ce3+ + H2O
Cf4+ + e 1 Cf3+
Cf3+ + e 1 Cf2+
Cf3+ + 3 e 1 Cf
Cf2+ + 2 e 1 Cf
Cl2(g) + 2 e 1 2 Cl–
HClO + H + + e 1 1/2 Cl2 + H2O
HClO + H+ + 2 e 1 Cl– + H2O
ClO– + H2O + 2 e 1 Cl– + 2 OH–
ClO2 + H+ + e 1 HClO2
HClO2 + 2 H+ + 2 e 1 HClO + H2O
HClO2 + 3 H+ + 3 e 1 1/2 Cl2 + 2 H2O
© 2000 by CRC PRESS LLC
E°/V
0.6992
0.5
0.308
0.2
–0.8
0.16
–0.46
1.593
0.320
0.1583
1.67
–1.6
–2.8
1.0873
1.066
1.331
1.574
1.596
0.761
1.482
1.423
0.61
0.373
0.330
0.77
–0.199
–3.80
–2.868
–3.02
0.2800
0.2801
0.3337
0.2412
0.2360
–0.4030
–0.3521
–0.809
–0.246
–0.658
–0.783
–2.336
–1.4373
1.72
1.715
3.3
–1.6
–1.94
–2.12
1.35827
1.611
1.482
0.81
1.277
1.645
1.628
Reaction
HClO2 + 3 H+ + 4 e 1 Cl– + 2 H2O
ClO2– + H2O + 2 e 1 ClO– + 2 OH–
ClO2– + 2 H2O + 4 e 1 Cl– + 4 OH–
ClO2(aq) + e 1 ClO2–
ClO3– + 2 H+ + e 1 ClO2 + H2O
ClO3– + 3 H+ + 2 e 1 HClO2 + H2O
ClO3– + 6 H+ + 5 e 1 1/2 Cl2 + 3 H2O
ClO3– + 6 H+ + 6 e 1 Cl– + 3 H2O
ClO3– + H2O + 2 e 1 ClO2– + 2 OH–
ClO3– + 3 H2O + 6 e 1 Cl– + 6 OH–
ClO4– + 2 H+ + 2 e 1 ClO3– H2O
ClO4– + 8 H+ + 7 e 1 1/2 Cl2 + 4 H2O
ClO4– + 8 H+ + 8 e 1 Cl– + 4 H2O
ClO4– + H2O + 2 e 1 ClO3– + 2 OH–
Cm4+ + e 1 Cm3+
Cm3+ + 3 e 1 Cm
Co2+ + 2 e 1 Co
Co3+ + e 1 Co2+
[Co(NH3)6]3+ + e 1 [Co(NH3)6]2+
Co(OH)2 + 2 e 1 Co + 2 OH–
Co(OH)3 + e 1 Co(OH)2 + OH–
Cr2+ + 2 e 1 Cr
Cr3+ + e 1 Cr2+
Cr3+ + 3 e 1 Cr
Cr2O72– + 14 H+ + 6 e 1 2 Cr3+ + 7 H2O
CrO2– + 2 H2O + 3 e 1 Cr + 4 OH–
HCrO4– + 7 H+ + 3 e 1 Cr3+ + 4 H2O
CrO2 + 4 H+ + e 1 Cr3+ + 2H2O
Cr(V) + e 1 Cr(IV)
CrO42– + 4 H2O + 3 e 1 Cr(OH)3 + 5 OH–
Cr(OH)3 + 3 e 1 Cr + 3 OH–
Cs+ + e 1 Cs
Cu+ + e 1 Cu
Cu2+ + e 1 Cu+
Cu2+ + 2 e 1 Cu
Cu2+ + 2 e 1 Cu(Hg)
Cu3+ + e 1 Cu2+
Cu2O3 + 6 H+ + 2e 1 2Cu2+ + 3 H2O
Cu2+ + 2 CN– + e 1 [Cu(CN)2]–
CuI2– + e 1 Cu + 2 I–
Cu2O + H2O + 2 e 1 2 Cu + 2 OH–
Cu(OH)2 + 2 e 1 Cu + 2 OH–
2 Cu(OH)2 + 2 e 1 Cu2O + 2 OH– + H2O
2 D+ + 2 e 1 D2
Dy2+ + 2 e 1 Dy
Dy3+ + 3 e 1 Dy
Dy3+ + e 1 Dy2+
Er2+ + 2 e 1 Er
Er3+ + 3 e 1 Er
Er3+ + e 1 Er2+
Es3+ + e 1 Es2+
Es3+ + 3 e 1 Es
Es2+ + 2 e 1 Es
Eu2+ + 2 e 1 Eu
Eu3+ + 3 e 1 Eu
E°/V
1.570
0.66
0.76
0.954
1.152
1.214
1.47
1.451
0.33
0.62
1.189
1.39
1.389
0.36
3.0
–2.04
–0.28
1.92
0.108
–0.73
0.17
–0.913
–0.407
–0.744
1.232
–1.2
1.350
1.48
1.34
–0.13
–1.48
–3.026
0.521
0.153
0.3419
0.345
2.4
2.0
1.103
0.00
–0.360
–0.222
–0.080
–0.013
–2.2
–2.295
–2.6
–2.0
–2.331
–3.0
–1.3
–1.91
–2.23
–2.812
–1.991
ELECTROCHEMICAL SERIES (continued)
TABLE 1
Alphabetical Listing (continued)
Reaction
Eu3+ + e 1 Eu2+
F2 + 2 H+ + 2 e 1 2 HF
F2 + 2 e 1 2 F–
F2O + 2 H+ + 4 e 1 H2O + 2 F–
Fe2+ + 2 e 1 Fe
Fe3+ + 3 e 1 Fe
Fe3+ + e 1 Fe2+
2 HFeO4– + 8 H+ + 6 e 1 Fe2O3 + 5 H2O
HFeO4– + 4 H+ + 3 e 1 FeOOH + 2 H2O
HFeO4– + 7 H+ + 3 e 1 Fe3+ + 4 H2O
Fe2O3 + 4 H+ + 2 e 1 2 FeOH+ + H2O
[Fe(CN)6]3– + e 1 [Fe(CN)6]4–
FeO42– + 8 H+ + 3 e 1 Fe3+ + 4 H2O
[Fe(bipy)2]3+ + e 1 Fe(bipy)2]2+
[Fe(bipy)3]3+ + e 1 Fe(bipy)3]2+
Fe(OH)3 + e 1 Fe(OH)2 + OH–
[Fe(phen)3]3+ + e 1 [Fe(phen)3]2+
[Fe(phen)3]3+ + e 1 [Fe(phen)3]2+ (1 molar H2SO4)
[Ferricinium]+ + e 1 ferrocene
Fm3++ e 1 Fm2+
Fm3+ + 3 e 1 Fm
Fm2+ + 2 e 1 Fm
Fr+ + e 1 Fr
Ga3+ + 3 e 1 Ga
Ga+ + e 1 Ga
GaOH2+ + H+ + 3 e 1 Ga + H2O
H2GaO–3 + H2O + 3 e 1 Ga + 4 OH–
Gd3+ + 3 e 1 Gd
Ge2+ + 2 e 1 Ge
Ge4+ + 4 e 1 Ge
Ge4+ + 2 e 1 Ge2+
GeO2 + 2 H+ + 2 e 1 GeO + H2O
H2GeO3 + 4 H+ + 4 e 1 Ge + 3 H2O
2 H+ + 2 e 1 H2
H2 + 2 e 1 2 H–
HO2 + H+ + e 1 H2O2
2 H2O + 2 e 1 H2 + 2 OH–
H2O2 + 2 H+ + 2 e 1 2 H2O
Hf4+ + 4 e 1 Hf
HfO2+ + 2 H+ + 4 e 1 Hf + H2O
HfO2 + 4 H+ + 4 e 1 Hf + 2 H2O
HfO(OH)2 + H2O + 4 e 1 Hf + 4 OH–
Hg2+ + 2 e 1 Hg
2 Hg2+ + 2 e 1 Hg22+
Hg22+ + 2 e 1 2 Hg
Hg2(ac)2 + 2 e 1 2 Hg + 2(ac)–
Hg2Br2 + 2 e 1 2 Hg + 2 Br–
Hg2Cl2 + 2 e 1 2 Hg + 2 Cl–
Hg2HPO4 + 2 e 1 2 Hg + HPO42–
Hg2I2 + 2 e 1 2 Hg + 2 I–
Hg2O + H2O + 2 e 1 2 Hg + 2 OH–
HgO + H2O + 2 e 1 Hg + 2 OH–
Hg(OH)2 + 2 H+ + 2 e 1 Hg + 2 H2O
Hg2SO4 + 2 e 1 2 Hg + SO42–
Ho2+ + 2 e 1 Ho
© 2000 by CRC PRESS LLC
E°/V
–0.36
3.053
2.866
2.153
–0.447
–0.037
0.771
2.09
2.08
2.07
0.16
0.358
2.20
0.78
1.03
–0.56
1.147
1.06
0.400
–1.1
–1.89
–2.30
–2.9
–0.549
–0.2
–0.498
–1.219
–2.279
0.24
0.124
0.00
–0.118
–0.182
0.00000
–2.23
1.495
–0.8277
1.776
–1.55
–1.724
–1.505
–2.50
0.851
0.920
0.7973
0.51163
0.13923
0.26808
0.6359
–0.0405
0.123
0.0977
1.034
0.6125
–2.1
Reaction
Ho3+ + 3 e 1 Ho
Ho3+ + e 1 Ho2+
I2 + 2 e 1 2 I–
I3– + 2 e 1 3 I–
H3IO62– + 2 e 1 IO–3 + 3 OH–
H5IO6 + H+ + 2 e 1 IO3– + 3 H2O
2 HIO + 2 H+ + 2 e 1 I2 + 2 H2O
HIO + H+ + 2 e 1 I– + H2O
IO– + H2O + 2 e 1 I– + 2 OH–
2 IO3– + 12 H+ + 10 e 1 I2 + 6 H2O
IO3– + 6 H+ + 6 e 1 I– + 3 H2O
IO3– + 2 H2O + 4 e 1 IO– + 4 OH–
IO3– + 3 H2O + 6 e 1 IO– + 6 OH–
In+ + e 1 In
In2+ + e 1 In+
In3+ + e 1 In2+
In3+ + 2 e 1 In+
In3+ + 3 e 1 In
In(OH)3 + 3 e 1 In + 3 OH–
In(OH)4– + 3 e 1 In + 4 OH–
In2O3 + 3 H2O + 6 e 1 2 In + 6 OH–
Ir3+ + 3 e 1 Ir
[IrCl6]2– + e 1 [IrCl6]3–
[IrCl6]3– + 3 e 1 Ir + 6 Cl–
Ir2O3 + 3 H2O + 6 e 1 2 Ir + 6 OH–
K+ + e 1 K
La3+ + 3 e 1 La
La(OH)3 + 3 e 1 La + 3 OH–
Li+ + e 1 Li
Lr3+ + 3 e 1 Lr
Lu3+ + 3 e 1 Lu
Md3+ + e 1 Md2+
Md3+ + 3 e 1 Md
Md2+ + 2 e 1 Md
Mg+ + e 1 Mg
Mg2+ + 2 e 1 Mg
Mg(OH)2 + 2 e 1 Mg + 2 OH–
Mn2+ + 2 e 1 Mn
Mn3+ + 3e 1 Mn2+
MnO2 + 4 H+ + 2 e 1 Mn2+ + 2 H2O
MnO4– + e 1 MnO42–
MnO4– + 4 H+ + 3 e 1 MnO2 + 2 H2O
MnO4– + 8 H+ + 5 e 1 Mn2+ + 4 H2O
MnO4– + 2 H2O + 3 e 1 MnO2 + 4 OH–
MnO42– + 2 H2O + 2 e 1 MnO2 + 4 OH–
Mn(OH)2 + 2 e 1 Mn + 2 OH–
Mn(OH)3 + e 1 Mn(OH)2 + OH–
Mn2O3 + 6 H+ + e 1 2 Mn2+ + 3 H2O
Mo3+ + 3 e 1 Mo
MoO2 + 4 H+ + 4 e 1 Mo + 4 H2O
H3Mo7O243– + 45 H+ + 42 e 1 7 Mo + 24 H2O
MoO3 + 6 H+ + 6 e 1 Mo + 3 H2O
N2 + 2 H2O + 6 H+ + 6 e 1 2 NH4OH
3 N2 + 2 H+ + 2 e 1 2 HN3
N5+ + 3 H+ + 2 e 1 2 NH4+
E°/V
–2.33
–2.8
0.5355
0.536
0.7
1.601
1.439
0.987
0.485
1.195
1.085
0.15
0.26
–0.14
–0.40
–0.49
–0.443
–0.3382
–0.99
–1.007
–1.034
1.156
0.8665
0.77
0.098
–2.931
–2.379
–2.90
–3.0401
–1.96
–2.28
–0.1
–1.65
–2.40
–2.70
–2.372
–2.690
–1.185
1.5415
1.224
0.558
1.679
1.507
0.595
0.60
–1.56
0.15
1.485
–0.200
–0.152
0.082
0.075
0.092
–3.09
1.275
ELECTROCHEMICAL SERIES (continued)
TABLE 1
Alphabetical Listing (continued)
Reaction
N2O + 2 H+ + 2 e 1 N2 + H2O
H2N2O2 + 2 H+ + 2 e 1 N2 + 2 H2O
N2O4 + 2 e 1 2 NO2–
N2O4 + 2 H+ + 2 e 1 2 NHO2
N2O4 + 4 H+ + 4 e 1 2 NO + 2 H2O
2 NH3OH+ + H+ + 2 e 1 N2H5+ + 2 H2O
2 NO + 2 H+ + 2 e 1 N2O + H2O
2 NO + H2O + 2 e 1 N2O + 2 OH–
HNO2 + H+ + e 1 NO + H2O
2 HNO2 + 4 H+ + 4 e 1 H2N2O2 + 2 H2O
2 HNO2 + 4 H+ + 4 e 1 N2O + 3 H2O
NO2– + H2O + e 1 NO + 2 OH–
2 NO2– + 2 H2O + 4 e 1 N2O22– + 4 OH–
2 NO2– + 3 H2O + 4 e 1 N2O + 6 OH–
NO3– + 3 H+ + 2 e 1 HNO2 + H2O
NO3– + 4 H+ + 3 e 1 NO + 2 H2O
2 NO3– + 4 H+ + 2 e 1 N2O4 + 2 H2O
NO3– + H2O + 2 e 1 NO2– + 2 OH–
2 NO3– + 2 H2O + 2 e 1 N2O4 + 4 OH–
Na+ + e 1 Na
Nb3+ + 3 e 1 Nb
NbO2 + 2 H+ + 2 e 1 NbO + H2O
NbO2 + 4 H+ + 4 e 1 Nb + 2 H2O
NbO + 2 H+ + 2 e 1 Nb + H2O
Nb2O5 + 10 H+ + 10 e 1 2 Nb + 5 H2O
Nd3+ + 3 e 1 Nd
Nd2+ + 2 e 1 Nd
Nd3+ + e 1 Nd2+
Ni2+ + 2 e 1 Ni
Ni(OH)2 + 2 e 1 Ni + 2 OH–
NiO2 + 4 H+ + 2 e 1 Ni2+ + 2 H2O
NiO2 + 2 H2O + 2 e 1 Ni(OH)2 + 2 OH–
No3+ + e 1 No2+
No3+ + 3 e 1 No
No2+ + 2 e 1 No
Np3+ + 3 e 1 Np
Np4+ + e 1 Np3+
NpO2 + H2O + H+ + e 1 Np(OH)3
O2 + 2 H+ + 2 e 1 H2O2
O2 + 4 H+ + 4 e 1 2 H2O
O2 + H2O + 2 e 1 HO2– + OH–
O2 + 2 H2O + 2 e 1 H2O2 + 2 OH–
O2 + 2 H2O + 4 e 1 4 OH–
O3 + 2 H+ + 2 e 1 O2 + H2O
O3 + H2O + 2 e 1 O2 + 2 OH–
O(g) + 2 H+ + 2 e 1 H2O
OH + e 1 OH–
HO2– + H2O + 2 e 1 3 OH–
OsO4 + 8 H+ + 8 e 1 Os + 4 H2O
OsO4 + 4 H+ + 4 e 1 OsO2 + 2 H2O
[Os(bipy)2]3+ + e 1 [Os(bipy)2]2+
[Os(bipy)3]3+ + e 1 [Os(bipy)3]2+
P(red) + 3 H+ + 3 e 1 PH3(g)
P(white) + 3 H+ + 3 e 1 PH3(g)
P + 3 H2O + 3 e 1 PH3(g) + 3 OH–
© 2000 by CRC PRESS LLC
E°/V
1.766
2.65
0.867
1.065
1.035
1.42
1.591
0.76
0.983
0.86
1.297
–0.46
–0.18
0.15
0.934
0.957
0.803
0.01
–0.85
–2.71
–1.099
–0.646
–0.690
–0.733
–0.644
–2.323
–2.1
–2.7
–0.257
–0.72
1.678
–0.490
1.4
–1.20
–2.50
–1.856
0.147
–0.962
0.695
1.229
–0.076
–0.146
0.401
2.076
1.24
2.421
2.02
0.878
0.838
1.02
0.81
0.80
–0.111
–0.063
–0.87
Reaction
H2P2– + e 1 P + 2 OH–
H3PO2 + H+ + e 1 P + 2 H2O
H3PO3 + 2 H+ + 2 e 1 H3PO2 + H2O
H3PO3 + 3 H+ + 3 e 1 P + 3 H2O
HPO32– + 2 H2O + 2 e 1 H2PO2– + 3 OH–
HPO32– + 2 H2O + 3 e 1 P + 5 OH–
H3PO4 + 2 H+ + 2 e 1 H3PO3 + H2O
PO43– + 2 H2O + 2 e 1 HPO32– + 3 OH–
Pa3+ + 3 e 1 Pa
Pa4+ + 4 e 1 Pa
Pa4+ + e 1 Pa3+
Pb2+ + 2 e 1 Pb
Pb2+ + 2 e 1 Pb(Hg)
PbBr2 + 2 e 1 Pb + 2 Br–
PbCl2 + 2 e 1 Pb + 2 Cl–
PbF2 + 2 e 1 Pb + 2 F–
PbHPO4 + 2 e 1 Pb + HPO42–
PbI2 + 2 e 1 Pb + 2 I–
PbO + H2O + 2 e 1 Pb + 2 OH–
PbO2 + 4 H+ + 2 e 1 Pb2+ + 2 H2O
HPbO2– + H2O + 2 e 1 Pb + 3 OH–
PbO2 + H2O + 2 e 1 PbO + 2 OH–
PbO2 + SO42– + 4 H+ + 2 e 1 PbSO4 + 2 H2O
PbSO4 + 2 e 1 Pb + SO42–
PbSO4 + 2 e 1 Pb(Hg) + SO42–
Pd2+ + 2 e 1 Pd
[PdCl4]2– + 2 e 1 Pd + 4 Cl–
[PdCl6]2– + 2 e 1 [PdCl4]2– + 2 Cl–
Pd(OH)2 + 2 e 1 Pd + 2 OH–
Pm2+ + 2 e 1 Pm
Pm3+ + 3 e 1 Pm
Pm3+ + e 1 Pm2+
Po4+ + 2 e 1 Po2+
Po4+ + 4 e 1 Po
Pr4+ + e 1 Pr3+
Pr2+ + 2 e 1 Pr
Pr3+ + 3 e 1 Pr
Pr3+ + e 1 Pr2+
Pt2+ + 2 e 1 Pt
[PtCl4]2– + 2 e 1 Pt + 4 Cl–
[PtCl6]2– + 2 e 1 [PtCl4]2– + 2 Cl–
Pt(OH)2 + 2 e 1 Pt + 2 OH–
PtO3 + 2 H+ + 2 e 1 PtO2 + H2O
PtO3 + 4 H+ + 2 e 1 Pt(OH)22+ + H2O
PtOH+ + H+ + 2 e 1 Pt + H2O
PtO2 + 2 H+ + 2 e 1 PtO + H2O
PtO2 + 4 H+ + 4 e 1 Pt + 2 H2O
Pu3+ + 3 e 1 Pu
Pu4+ + e 1 Pu3+
Pu5+ + e 1 Pu4+
PuO2(OH)2 + 2 H+ + 2 e 1 Pu(OH)4
PuO2(OH)2 + H+ + e 1 PuO2OH + H2O
Ra2+ + 2 e 1 Ra
Rb+ + e 1 Rb
Re3+ + 3 e 1 Re
E°/V
–1.82
–0.508
–0.499
–0.454
–1.65
–1.71
–0.276
–1.05
–1.34
–1.49
–1.9
–0.1262
–0.1205
–0.284
–0.2675
–0.3444
–0.465
–0.365
–0.580
1.455
–0.537
0.247
1.6913
–0.3588
–0.3505
0.951
0.591
1.288
0.07
–2.2
–2.30
–2.6
0.9
0.76
3.2
–2.0
–2.353
–3.1
1.18
0.755
0.68
0.14
1.7
1.5
1.2
1.01
1.00
–2.031
1.006
1.099
1.325
1.062
–2.8
–2.98
0.300
ELECTROCHEMICAL SERIES (continued)
TABLE 1
Alphabetical Listing (continued)
Reaction
ReO4– + 4 H+ + 3 e 1 ReO2 + 2 H2O
ReO2 + 4 H+ + 4 e 1 Re + 2 H2O
ReO4– + 2 H+ + e 1 ReO3 + H2O
ReO4– + 4 H2O + 7 e 1 Re + 8 OH–
ReO4– + 8 H+ + 7 e 1 Re + 4 H2O
Rh+ + e 1 Rh
Rh+ + 2e1 Rh
Rh3+ + 3 e 1 Rh
[RhCl6]3– + 3 e 1 Rh + 6 Cl–
RhOH2+ + H+ + 3 e 1 Rh + H2O
Ru2+ + 2 e 1 Ru
Ru3+ + e 1 Ru2+
RuO2 + 4 H+ + 2 e 1 Ru2+ + 2 H2O
RuO4– + e 1 RuO42–
RuO4 + e 1 RuO4–
RuO4 + 6 H+ + 4 e 1 Ru(OH)22+ + 2 H2O
RuO4 + 8 H+ + 8 e 1 Ru + 4 H2O
[Ru(bipy)3)3+ + e–1 [Ru(bipy)3]2+
[Ru(H2O)6]3+ + e–1 [Ru(H2O)6]2+
[Ru(NH3)6]3+ + e–1 [Ru(NH3)6]2+
[Ru(en)3]3+ + e –1 [Ru(en)3]2+
[Ru(CN)6]3– + e–1 [Ru(CN)6]4–
S + 2 e 1 S2–
S + 2H+ + 2 e 1 H2S(aq)
S + H2O + 2 e 1 SH– + OH–
2 S + 2 e 1 S22–
S2O62– + 4 H+ + 2 e 1 2 H2SO3
S2O82– + 2 e 1 2 SO42–
S2O82– + 2 H+ + 2 e 1 2 HSO4–
S4O62– + 2 e 1 2 S2O32–
2 H2SO3 + H+ + 2 e 1 HS2O4– + 2 H2O
H2SO3 + 4 H+ + 4 e 1 S + 3 H2O
2 SO32– + 2 H2O + 2 e 1 S2O42– + 4 OH–
2 SO32– + 3 H2O + 4 e 1 S2O32– + 6 OH–
SO42– + 4 H+ + 2 e 1 H2SO3 + H2O
2 SO42– + 4 H+ + 2 e 1 S2O62– + H2O
SO42– + H2O + 2 e 1 SO32– + 2 OH–
Sb + 3 H+ + 3 e 1 SbH3
Sb2O3 + 6 H+ + 6 e 1 2 Sb + 3 H2O
Sb2O5 (senarmontite) + 4 H+ + 4 e 1 Sb2O3 + 2 H2O
Sb2O5 (valentinite) + 4 H+ + 4 e 1 Sb2O3 + 2 H2O
Sb2O5 + 6 H+ + 4 e 1 2 SbO+ + 3 H2O
SbO+ + 2 H+ + 3 e 1 Sb + 2 H2O
SbO2– + 2 H2O + 3 e 1 Sb + 4 OH–
SbO3– + H2O + 2 e 1 SbO2– + 2 OH–
Sc3+ + 3 e 1 Sc
Se + 2 e 1 Se2–
Se + 2 H+ + 2 e 1 H2Se(aq)
H2SeO3 + 4 H+ + 4 e 1 Se + 3 H2O
Se + 2 H+ + 2 e 1 H2Se
SeO32– + 3 H2O + 4 e 1 Se + 6 OH–
SeO42– + 4 H+ + 2 e 1 H2SeO3 + H2O
SeO42– + H2O + 2 e 1 SeO32– + 2 OH–
SiF62– + 4 e 1 Si + 6 F–
SiO + 2 H+ + 2 e 1 Si + H2O
© 2000 by CRC PRESS LLC
E°/V
0.510
0.2513
0.768
–0.584
0.368
0.600
0.600
0.758
0.431
0.83
0.455
0.2487
1.120
0.59
1.00
1.40
1.038
1.24
0.23
0.10
0.210
0.86
–0.47627
0.142
–0.478
–0.42836
0.564
2.010
2.123
0.08
–0.056
0.449
–1.12
–0.571
0.172
–0.22
–0.93
–0.510
0.152
0.671
0.649
0.581
0.212
–0.66
–0.59
–2.077
–0.924
–0.399
0.74
–0.082
–0.366
1.151
0.05
–1.24
–0.8
Reaction
SiO2 (quartz) + 4 H+ + 4 e 1 Si + 2 H2O
SiO32– + 3 H2O + 4 e 1 Si + 6 OH–
Sm3+ + e 1 Sm2+
Sm3+ + 3 e 1 Sm
Sm2+ + 2 e 1 Sm
Sn2+ + 2 e 1 Sn
Sn4+ + 2 e 1 Sn2+
Sn(OH)3+ + 3 H+ + 2 e 1 Sn2+ + 3 H2O
SnO2 + 4 H+ + 2 e–1 Sn2+ + 2 H2O
SnO2 + 4 H+ + 4 e 1 Sn + 2 H2O
SnO2 + 3 H+ + 2 e 1 SnOH+ + H2O
SnO2 + 2 H2O + 4 e 1 Sn + 4 OH–
HSnO2– + H2O + 2 e 1 Sn + 3 OH–
Sn(OH)62– + 2 e 1 HSnO2– + 3 OH– + H2O
Sr+ + e 1 Sr
Sr2+ + 2 e 1 Sr
Sr2+ + 2 e 1 Sr(Hg)
Sr(OH)2 + 2 e 1 Sr + 2 OH–
Ta2O5 + 10 H+ + 10 e 1 2 Ta + 5 H2O
Ta3+ + 3 e 1 Ta
Tc2+ + 2 e 1 Tc
TcO4– + 4 H+ + 3 e 1 TcO2 + 2 H2O
Tc3+ + e 1 Tc2+
TcO4– + 8 H+ + 7 e 1 Tc + 4 H2O
Tb4+ + e 1 Tb3+
Tb3+ + 3 e 1 Tb
Te + 2 e 1 Te2–
Te + 2 H+ + 2 e 1 H2Te
Te4+ + 4 e 1 Te
TeO2 + 4 H+ + 4 e 1 Te + 2 H2O
TeO32– + 3 H2O + 4 e 1 Te + 6 OH–
TeO4– + 8 H+ + 7 e 1 Te + 4 H2O
H6TeO6 + 2 H+ + 2 e 1 TeO2 + 4 H2O
Th4+ + 4 e 1 Th
ThO2 + 4 H+ + 4 e 1 Th + 2 H2O
Th(OH)4 + 4 e 1 Th + 4 OH–
Ti2+ + 2 e 1 Ti
Ti3+ + e 1 Ti2+
TiO2 + 4 H+ + 2 e 1 Ti2+ + 2 H2O
Ti3+ + 3 e 1 Ti
TiOH3+ + H+ + e 1 Ti3+ + H2O
Tl+ + e 1 Tl
Tl+ + e 1 Tl(Hg)
Tl3+ + 2 e 1 Tl+
Tl3+ + 3 e 1 Tl
TlBr + e 1 Tl + Br–
TlCl + e 1 Tl + Cl–
TlI + e 1 Tl + I–
Tl2O3 + 3 H2O + 4 e 1 2 Tl+ + 6 OH–
TlOH + e 1 Tl + OH–
Tl(OH)3 + 2 e 1 TlOH + 2 OH–
Tl2SO4 + 2 e 1 Tl + SO42–
Tm3+ + e 1 Tm2+
Tm3+ + 3 e 1 Tm
Tm2+ + 2 e 1 Tm
E°/V
0.857
–1.697
–1.55
–2.304
–2.68
–0.1375
0.151
0.142
–0.094
–0.117
–0.194
–0.945
–0.909
–0.93
–4.10
–2.899
–1.793
–2.88
–0.750
–0.6
0.400
0.782
0.3
0.472
3.1
–2.28
–1.143
–0.793
0.568
0.593
–0.57
0.472
1.02
–1.899
–1.789
–2.48
–1.630
–0.9
–0.502
–1.37
–0.055
–0.336
–0.3338
1.252
0.741
–0.658
–0.5568
–0.752
0.02
–0.34
–0.05
–0.4360
–2.2
–2.319
–2.4
ELECTROCHEMICAL SERIES (continued)
TABLE 1
Alphabetical Listing (continued)
Reaction
U3+ + 3 e 1 U
U4+ + e 1 U3+
UO2+ + 4 H+ + e 1 U4+ + 2 H2O
UO22+ + e 1 UO+2
UO22+ + 4 H+ + 2 e 1 U4+ + 2 H2O
UO22+ + 4 H+ + 6 e 1 U + 2 H2O
V2+ + 2 e 1 V
V3+ + e 1 V2+
VO2+ + 2 H+ + e 1 V3+ + H2O
VO2+ + 2 H+ + e 1 VO2+ + H2O
V2O5 + 6 H+ + 2 e 1 2 VO2+ + 3 H2O
V2O5 + 10 H+ + 10 e 1 2 V + 5 H2O
V(OH)4+ + 2 H+ + e 1 VO2+ + 3 H2O
V(OH)4+ + 4 H+ + 5 e 1 V + 4 H2O
[V(phen)3]3+ + e 1 [V(phen)3]2+
W3+ + 3 e 1 W
W2O5 + 2 H+ + 2 e 1 2 WO2 + H2O
WO2 + 4 H+ + 4 e 1 W + 2 H2O
WO3 + 6 H+ + 6 e 1 W + 3 H2O
WO3 + 2 H+ + 2 e 1 WO2 + H2O
E°/V
–1.798
–0.607
0.612
0.062
0.327
–1.444
–1.175
–0.255
0.337
0.991
0.957
–0.242
1.00
–0.254
0.14
0.1
–0.031
–0.119
–0.090
0.036
Reaction
2 WO3 + 2 H+ + 2 e 1 W2O5 + H2O
H4XeO6 + 2 H+ + 2 e 1 XeO3 + 3 H2O
XeO3 + 6 H+ + 6 e 1 Xe + 3 H2O
XeF + e 1 Xe + F–
Y3+ + 3 e 1 Y
Yb3+ + e 1 Yb2+
Yb3+ + 3 e 1 Yb
Yb2+ + 2 e 1 Yb
Zn2+ + 2 e 1 Zn
Zn2+ + 2 e 1 Zn(Hg)
ZnO22– + 2 H2O + 2 e 1 Zn + 4 OH–
ZnSO4 ⋅ 7 H2O + 2 e = Zn(Hg) + SO42– + 7 H2O
(Saturated ZnSO4)
ZnOH+ + H+ + 2 e 1 Zn + H2O
Zn(OH)42– + 2 e 1 Zn + 4 OH–
Zn(OH)2 + 2 e 1 Zn + 2 OH–
ZnO + H2O + 2 e 1 Zn + 2 OH–
ZrO2 + 4 H+ + 4 e 1 Zr + 2 H2O
ZrO(OH)2 + H2O + 4 e 1 Zr + 4 OH–
Zr4+ + 4 e 1 Zr
E°/V
–0.029
2.42
2.10
3.4
–2.372
–1.05
–2.19
–2.76
–0.7618
–0.7628
–1.215
–0.7993
–0.497
–1.199
–1.249
–1.260
–1.553
–2.36
–1.45
TABLE 2
Reduction Reactions Having E° Values More Positive than that of the Standard Hydrogen Electrode
Reaction
2 H+ + 2 e 1 H2
CuI2– + e 1 Cu + 2 I–
Ge4+ + 2 e 1 Ge2+
NO3– + H2O + 2 e 1 NO2– + 2 OH–
Tl2O3 + 3 H2O + 4 e 1 2 Tl+ + 6 OH–
SeO42– + H2O + 2 e 1 SeO32– + 2 OH–
WO3 + 2 H+ + 2 e 1 WO2 + H2O
UO22+ + e = UO2+
Pd(OH)2 + 2 e 1 Pd + 2 OH–
AgBr + e 1 Ag + Br–
MoO3 + 6 H+ + 6 e 1 Mo + 3 H2O
S4O62– + 2 e 1 2 S2O32–
H3Mo7O243– + 45 H+ + 42 e 1 7 Mo + 24 H2O
AgSCN + e 1 Ag + SCN–
N2 + 2 H2O + 6 H+ + 6 e 1 2 NH4OH
HgO + H2O + 2 e 1 Hg + 2 OH–
Ir2O3 + 3 H2O + 6 e 1 2 Ir + 6 OH–
2 NO + 2 e 1 N2O22–
[Ru(NH3)6]3+ + e 1 [Ru(NH3)6]2+
W3+ + 3 e 1 W
[Co(NH3)6]3+ + e 1 [Co(NH3)6]2+
Hg2O + H2O + 2 e 1 2 Hg + 2 OH–
Ge4+ + 4 e 1 Ge
Hg2Br2 + 2 e 1 2 Hg + 2 Br–
Pt(OH)2 + 2 e 1 Pt + 2 OH–
[V(phen)3]3+ + e 1 [V(phen)3]2+
S + 2H+ + 2 e 1 H2S(aq)
© 2000 by CRC PRESS LLC
E°/V
0.00000
0.00
0.00
0.01
0.02
0.05
0.036
0.062
0.07
0.07133
0.075
0.08
0.082
0.8951
0.092
0.0977
0.098
0.10
0.10
0.1
0.108
0.123
0.124
0.13923
0.14
0.14
0.142
Reaction
Sn(OH)3+ + 3 H+ + 2 e 1 Sn2+ + 3 H2O
Np4+ + e 1 Np3+
Ag4[Fe(CN)6] + 4 e 1 4 Ag + [Fe(CN)6]4–
IO3– + 2 H2O + 4 e 1 IO– + 4 OH–
Mn(OH)3 + e 1 Mn(OH)2 + OH–
2 NO2– + 3 H2O + 4 e 1 N2O + 6 OH–
Sn4+ + 2 e 1 Sn2+
Sb2O3 + 6 H+ + 6 e 1 2 Sb + 3 H2O
Cu2+ + e 1 Cu+
BiOCl + 2 H+ + 3 e 1 Bi + Cl– + H2O
BiCl4– + 3 e 1 Bi + 4 Cl–
Fe2O3 + 4 H+ + 2 e 1 2 FeOH+ + H2O
Co(OH)3 + e 1 Co(OH)2 + OH–
SO42– + 4 H+ + 2 e 1 H2SO3 + H2O
Bi3+ + 2 e 1 Bi+
[Ru(en)3]3+ + e 1 [Ru(en)3]2+
SbO+ + 2 H+ + 3 e 1 Sb + 2 H2O
AgCl + e 1 Ag + Cl–
[Ru(H2O)6]3+ + e 1 [Ru(H2O)6]2+
As2O3 + 6 H+ + 6 e 1 2 As + 3 H2O
Calomel electrode, saturated NaCl (SSCE)
Ge2+ + 2 e 1 Ge
Ru3+ + e 1 Ru2+
Calomel electrode, saturated KCl
PbO2 + H2O + 2 e 1 PbO + 2 OH–
HAsO2 + 3 H+ + 3 e 1 As + 2 H2O
Ru3+ + e 1 Ru2+
E°/V
0.142
0.147
0.1478
0.15
0.15
0.15
0.151
0.152
0.153
0.1583
0.16
0.16
0.17
0.172
0.2
0.210
0.212
0.22233
0.23
0.234
0.2360
0.24
0.24
0.2412
0.247
0.248
0.2487
MOLAR CONDUCTIVITY OF AQUEOUS HF, HCl, HBr, AND HI
The molar conductivity Λ of an electrolyte solution is defined as the conductivity divided by amount-of-substance concentration. The customary
unit is S cm2mol-1 (i.e., Ω-1 cm2mol-1). The first part of this table gives the molar conductivity of the hydrohalogen acids at 25°C as a function of the
concentration in mol/L. The second part gives the temperature dependence of Λ for HCl and HBr. More extensive tables and mathematical
representations may be found in the reference.
REFERENCE
Hamer, W.J., and DeWane, H.J., Electrolytic Conductance and the Conductances of the Hydrohalogen Acids in Water, Natl. Stand. Ref. Data Sys.Natl. Bur. Standards (U.S.), No. 33, 1970.
c/mol L–1
HF
HCl
HBr
HI
Inf. dil.
0.0001
0.0005
0.001
0.005
0.01
0.05
0.10
0.5
1.0
1.5
2.0
2.5
3.0
405.1
426.1
424.5
422.6
421.2
415.7
411.9
398.9
391.1
360.7
332.2
305.8
281.4
258.9
237.6
427.7
425.9
424.3
422.9
417.6
413.7
400.4
391.9
361.9
334.5
307.6
281.7
257.8
236.8
426.4
424.6
423.0
421.7
416.4
412.8
400.8
394.0
369.8
343.9
316.4
288.9
262.5
237.9
c/mol L–1
128.1
96.1
50.1
39.1
26.3
24.3
–20°C
–10°C
0°C
c/mol L–1
HF
3.5
4.0
4.5
5.0
5.5
6.0
6.5
7.0
7.5
8.0
8.5
9.0
9.5
10.0
10°C
HCl
HBr
HI
218.3
200.0
183.1
167.4
152.9
139.7
127.7
116.9
107.0
98.2
90.3
83.1
76.6
70.7
217.5
199.4
182.4
166.5
151.8
138.2
125.7
114.2
103.8
94.4
85.8
215.4
195.1
176.8
160.4
145.5
131.7
118.6
105.7
20°C
30°C
40°C
50°C
336.4
312.2
287.5
262.9
239.8
219.3
201.6
185.6
170.6
156.6
143.6
131.5
120.4
110.2
100.9
92.4
84.7
77.8
71.5
65.8
60.7
56.1
51.9
48.0
44.4
386.8
359.0
331.1
303.3
277.0
253.3
232.9
214.2
196.6
180.2
165.0
151.0
138.2
126.4
115.7
106.1
97.3
89.4
82.3
75.9
70.1
64.9
60.1
55.6
51.4
436.9
402.9
371.6
342.4
315.2
289.3
263.9
242.2
222.5
204.1
187.1
171.3
156.9
143.3
131.6
120.6
110.7
101.7
93.6
86.3
79.6
73.6
68.0
62.8
57.9
482.4
445.3
410.8
378.2
347.6
319.0
292.1
268.2
246.7
226.5
207.7
190.3
174.3
159.7
146.2
134.0
123.0
112.9
103.9
95.7
88.4
81.7
75.6
70.0
64.8
HCl
0.5
1.0
1.5
2.0
2.5
3.0
3.5
4.0
4.5
5.0
5.5
6.0
6.5
7.0
7.5
8.0
8.5
9.0
9.5
10.0
10.5
11.0
11.5
12.0
12.5
85.5
79.3
73.7
68.5
63.6
58.9
54.4
50.2
46.3
42.7
39.4
36.4
33.6
31.2
28.9
26.8
24.9
23.1
21.4
131.7
120.8
111.3
102.7
94.9
87.8
81.1
74.9
69.1
63.7
58.6
54.0
49.8
45.9
42.3
39.1
36.1
33.4
31.0
28.7
26.7
228.7
211.7
196.2
182.0
168.5
154.6
139.6
129.2
119.5
110.3
101.7
93.7
86.2
79.3
73.0
67.1
61.7
56.8
52.3
48.2
44.5
41.1
38.0
35.3
32.7
283.0
261.6
241.5
222.7
205.1
188.5
172.2
158.1
145.4
133.5
122.5
112.3
103.0
94.4
86.5
79.4
72.9
67.1
61.8
57.0
52.7
48.8
45.3
42.0
39.0
5-90
MOLAR CONDUCTIVITY OF AQUEOUS HF, HCl, HBr, AND HI (continued)
c/mol
L–1
–20°C
–10°C
0°C
10°C
20°C
30°C
40°C
50°C
347.0
329.0
298.9
271.8
244.8
222.2
203.2
186.8
171.2
155.7
142.1
129.6
118.0
107.1
398.9
380.4
340.6
314.1
281.7
255.0
234.4
214.2
195.1
178.2
162.8
148.0
134.1
121.4
453.6
418.6
381.8
350.5
316.0
287.8
263.7
239.7
218.8
199.6
181.4
165.4
150.5
136.3
496.8
465.2
421.4
387.4
349.1
318.6
291.9
266.9
242.6
221.3
201.8
183.4
166.3
150.8
HBr
0.5
1.0
1.5
2.0
2.5
3.0
3.5
4.0
4.5
5.0
5.5
6.0
6.5
7.0
84.0
78.0
72.3
67.0
61.8
56.8
51.9
150.8
136.8
125.7
116.1
107.5
99.0
91.4
84.2
77.2
70.7
64.6
240.9
229.6
209.5
188.6
171.7
157.2
144.1
132.3
123.0
112.6
103.1
94.3
86.0
78.4
295.9
276.0
254.9
231.3
208.3
189.5
174.6
160.2
146.4
134.0
122.7
112.0
102.0
92.6
5-91
STANDARD KCl SOLUTIONS FOR CALIBRATING CONDUCTIVITY CELLS
This table presents recommended electrolytic conductivity (k) values for aqueous potassium chloride solutions with molalities of 0.01 mol/kg,
0.1 mol/kg and 1.0 mol/kg at temperatures from 0˚C to 50˚C. The values, which are based on measurements at the National Institute of Standards
and Technology, provide primary standards for the calibration of conductivity cells. The measurements at 0.01 and 0.1 molal are described in
Reference 1, while those at 1.0 molal are in Reference 2. Temperatures are given on the ITS-90 scale. The uncertainty in the conductivity is about
0.03% for the 0.01 molal values and about 0.04% for the 0.1 and 1.0 molal values. The conductivity of water saturated with atmospheric CO2 is
given in the last column. These values were subtracted from the original measurements to give the values in the second, third, and fourth
columns. All k values are given in units of 10-4 S/m (numerically equal to mS/cm).
The assistance of Kenneth W. Pratt is appreciated.
REFERENCES
1. Wu, Y.C., Koch, W.F., and Pratt, K.W., J. Res. Natl. Inst. Stand. Technol. 96, 191, 1991.
2. Wu, Y.C., Koch, W.F., Feng, D., Holland, L.A., Juhasz, E., Arvay, E., and Tomek, A., J. Res. Natl. Inst. Stand. Technol. 99, 241, 1994.
3. Pratt, K.W., Koch, W.F., Wu, Y.C., and Berezansky, P.A., Pure Appl. Chem. 73, 1783, 2001.
104 k/S m-1
t/˚C
0.01 m KCl
0.1 m KCl
1.0 m KCl
0
5
10
15
18
20
25
30
35
40
45
50
772.92
890.96
1 013.95
1 141.45
1 219.93
1 273.03
1 408.23
1 546.63
1 687.79
1 831.27
1 976.62
2 123.43
7 116.85
8 183.70
9 291.72
10 437.1
11 140.6
11 615.9
12 824.6
14 059.2
15 316.0
16 591.0
17 880.6
19 180.9
63 488
72 030
80 844
89 900
—99 170
108 620
118 240
127 970
137 810
147 720
157 670
5-91
H2O (CO2 sat.)
0.58
0.68
0.79
0.89
0.95
0.99
1.10
1.20
1.30
1.40
1.51
1.61
EQUIVALENT CONDUCTIVITY OF ELECTROLYTES IN AQUEOUS SOLUTION
Petr Vanýsek
This table gives the equivalent (molar) conductivity Λ at 25°C for some common electrolytes in aqueous solution at concentrations up to 0.1 mol/
L. The units of Λ are 10–4 m2 S mol–1.
For very dilute solutions, the equivalent conductivity for any electrolyte of concentration c can be approximately calculated using the DebyeHückel-Onsager equation, which can be written for a symmetrical (equal charge on cation and anion) electrolyte as
Λ = Λ° – (A + BΛ°)c1/2
For a solution at 25°C and both cation and anion with charge *1*, the constants are A = 60.20 and B = 0.229. Λ° can be found from the next table, “Ionic
Conductivity and Diffusion at Infinite Dilution”. The equation is reliable for c < 0.001 mol/L; with higher concentration the error increases.
Compound
Infinite
dilution
Concentration (mol/L)
0.0005
0.001
0.005
Λ°
AgNO3
1/2BaCl2
1/2CaCl2
1/2Ca(OH)2
1/2CuSO4
HCl
KBr
KCl
KClO4
1/3K3Fe(CN)6
1/4K4Fe(CN)6
KHCO3
KI
KIO4
KNO3
KMnO4
KOH
KReO4
1/3LaCl3
LiCl
LiClO4
1/2MgCl2
NH4Cl
NaCl
NaClO4
NaI
NaOOCCH3
NaOH
Na picrate
1/2Na2SO4
1/2SrCl2
1/2ZnSO4
133.29
139.91
135.77
258
133.6
425.95
151.9
149.79
139.97
174.5
184
117.94
150.31
127.86
144.89
134.8
271.5
128.20
145.9
114.97
105.93
129.34
149.6
126.39
117.42
126.88
91.0
247.7
80.45
129.8
135.73
132.7
0.01
0.02
0.05
0.1
121.35
119.03
115.59
214
72.16
407.04
140.41
138.27
127.86
—
122.76
107.17
139.38
114.08
132.34
—
—
114.49
115.3
104.60
96.13
109.99
138.25
115.70
106.91
116.64
81.20
—
—
106.73
115.48
74.20
115.18
111.42
108.42
—
59.02
398.89
135.61
133.30
121.56
—
107.65
—
134.90
106.67
126.25
—
219
106.40
106.2
100.06
92.15
103.03
133.22
111.01
102.35
112.73
76.88
—
66.3
97.70
108.20
61.17
109.09
105.14
102.41
—
50.55
391.13
131.32
128.90
115.14
—
97.82
—
131.05
98.2
120.34
113
213
97.40
99.1
95.81
88.52
97.05
128.69
106.69
98.38
108.73
72.76
—
61.8
89.94
102.14
52.61
Λ
131.29
135.89
131.86
—
121.6
422.53
149.8
147.74
138.69
166.4
—
116.04
148.2
125.74
142.70
132.7
—
126.03
139.6
113.09
104.13
125.55
147.5
124.44
115.58
125.30
89.2
245.5
78.7
125.68
131.84
121.3
130.45
134.27
130.30
—
115.20
421.15
148.9
146.88
137.80
163.1
167.16
115.28
143.32
124.88
141.77
131.9
234
125.12
137.0
112.34
103.39
124.15
146.7
123.68
114.82
124.19
88.5
244.6
78.6
124.09
130.27
114.47
127.14
127.96
124.19
233
94.02
415.59
146.02
143.48
134.09
150.7
146.02
112.18
144.30
121.18
138.41
—
230
121.31
127.5
109.35
100.52
118.25
134.4
120.59
111.70
121.19
85.68
240.7
75.7
117.09
124.18
95.44
5-92
124.70
123.88
120.30
226
83.08
411.80
143.36
141.20
131.39
—
134.76
110.03
142.11
118.45
132.75
126.5
228
118.49
121.8
107.27
98.56
114.49
141.21
118.45
109.54
119.18
83.72
237.9
73.7
112.38
120.23
84.87
IONIC CONDUCTIVITY AND DIFFUSION AT INFINITE DILUTION
Petr Vanýsek
This table gives the molar (equivalent) conductivity λ for common ions at infinite dilution. All values refer to aqueous solutions at 25°C. It also
lists the diffusion coefficient D of the ion in dilute aqueous solution, which is related to λ through the equation
(
)
D = RT / F 2 (λ / z )
where R is the molar gas constant, T the temperature, F the Faraday constant, and z the charge on the ion. The variation with temperature is fairly sharp;
for typical ions, λ and D increase by 2 to 3% per degree as the temperature increases from 25°C.
The diffusion coefficient for a salt, Dsalt, may be calculated from the D+ and D– values of the constituent ions by the relation
Dsalt =
(z+ + z– )D+ D–
z + D+ + z – D–
For solutions of simple, pure electrolytes (one positive and one negative ionic species), such as NaCl, equivalent ionic conductivity Λ°, which is
the conductivity per unit concentration of charge, is defined as
Λ° = λ + + λ –
where λ+ and λ– are equivalent ionic conductivities of the cation and anion. The more general formula is
Λ° = ν+λ+ + ν−λ−
where ν+ and ν− refer to the number of moles of cations and anions to which one mole of the electrolyte gives a rise in the solution.
REFERENCES
1.
2.
3.
4.
5.
Gray, D. E., Ed., American Institute of Physics Handbook, McGraw-Hill, New York, 1972, 2—226.
Robinson, R. A., and Stokes, R. H., Electrolyte Solutions, Butterworths, London, 1959.
Lobo, V. M. M., and Quaresma, J. L., Handbook of Electrolyte Solutions, Physical Science Data Series 41, Elsevier, Amsterdam, 1989.
Conway, B. E., Electrochemical Data, Elsevier, Amsterdam, 1952.
Milazzo, G., Electrochemistry: Theoretical Principles and Practical Applications, Elsevier, Amsterdam, 1963.
Ion
λ
10-4 m2 S mol-1
D
10-5 cm2 s-1
Inorganic Cations
Ag+
1/3Al3+
1/2Ba2+
1/2Be2+
1/2Ca2+
1/2Cd2+
1/3Ce3+
1/2Co2+
1/3[Co(NH3)6]3+
1/3[Co(en)3]3+
1/6[Co2(trien)3]6+
1/3Cr3+
Cs+
1/2Cu2+
D+
1/3Dy3+
1/3Er3+
1/3Eu3+
1/2Fe2+
1/3Fe3+
1/3Gd3+
H+
1/2Hg2+
1/2Hg2+
© 2000 by CRC PRESS LLC
61.9
61
63.6
45
59.47
54
69.8
55
101.9
74.7
69
67
77.2
53.6
249.9
65.6
65.9
67.8
54
68
67.3
349.65
68.6
63.6
1.648
0.541
0.847
0.599
0.792
0.719
0.620
0.732
0.904
0.663
0.306
0.595
2.056
0.714
6.655
0.582
0.585
0.602
0.719
0.604
0.597
9.311
0.913
0.847
Ion
1/3Ho3+
K+
1/3La3+
Li+
1/2Mg2+
1/2Mn2+
NH4+
N2H5+
Na+
1/3Nd3+
1/2Ni2+
1/4[Ni2(trien)3]4+
1/2Pb2+
1/3Pr3+
1/2Ra2+
Rb+
1/3Sc3+
1/3Sm3+
1/2Sr2+
Tl+
1/3Tm3+
1/2UO22+
1/3Y3+
1/3Yb3+
1/2Zn2+
λ
10-4 m2 S mol-1
66.3
73.48
69.7
38.66
53.0
53.5
73.5
59
50.08
69.4
49.6
52
71
69.5
66.8
77.8
64.7
68.5
59.4
74.7
65.4
32
62
65.6
52.8
D
10-5 cm2 s-1
0.589
1.957
0.619
1.029
0.706
0.712
1.957
1.571
1.334
0.616
0.661
0.346
0.945
0.617
0.889
2.072
0.574
0.608
0.791
1.989
0.581
0.426
0.550
0.582
0.703
IONIC CONDUCTIVITY AND DIFFUSION AT INFINITE DILUTION (continued)
Ion
λ
10-4 m2 S mol-1
D
10-5 cm2 s-1
Inorganic Anions
Au(CN)2Au(CN)4B(C6H5)4BrBr3BrO3CNCNO1/2CO32ClClO2ClO3ClO41/3[Co(CN)6]31/2CrO42F1/4[Fe(CN)6]41/3[Fe(CN)6]3H2AsO4HCO3HF21/2HPO42H2PO4H2PO2HSHSO3HSO4H2SbO4IIO3IO4MnO41/2MoO42N(CN)2NO2NO3NH2SO3N3OCNODOHPF61/2PO3F21/3PO431/4P2O741/3P3O931/5P3O105ReO4SCN1/2SO321/2SO421/2S2O321/2S2O421/2S2O621/2S2O82Sb(OH)6SeCN-
© 2000 by CRC PRESS LLC
50
36
21
78.1
43
55.7
78
64.6
69.3
76.31
52
64.6
67.3
98.9
85
55.4
110.4
100.9
34
44.5
75
57
36
46
65
58
52
31
76.8
40.5
54.5
61.3
74.5
54.5
71.8
71.42
48.3
69
64.6
119
198
56.9
63.3
92.8
96
83.6
109
54.9
66
72
80.0
85.0
66.5
93
86
31.9
64.7
1.331
0.959
0.559
2.080
1.145
1.483
2.077
1.720
0.923
2.032
1.385
1.720
1.792
0.878
1.132
1.475
0.735
0.896
0.905
1.185
1.997
0.759
0.959
1.225
1.731
1.545
1.385
0.825
2.045
1.078
1.451
1.632
1.984
1.451
1.912
1.902
1.286
1.837
1.720
3.169
5.273
1.515
0.843
0.824
0.639
0.742
0.581
1.462
1.758
0.959
1.065
1.132
0.885
1.238
1.145
0.849
1.723
λ
10-4 m2 S mol-1
Ion
1/2SeO421/2WO42-
75.7
69
D
10-5 cm2 s-1
1.008
0.919
Organic Cations
Benzyltrimethylammonium+
Isobutylammonium+
Butyltrimethylammonium+
Decylpyridinium+
Decyltrimethylammonium+
Diethylammonium+
Dimethylammonium+
Dipropylammonium+
Dodecylammonium+
Dodecyltrimethylammonium+
Ethanolammonium+
Ethylammonium+
Ethyltrimethylammonium+
Hexadecyltrimethylammonium+
Hexyltrimethylammonium+
Histidyl+
Hydroxyethyltrimethylarsonium+
Methylammonium+
Octadecylpyridinium+
Octadecyltributylammonium+
Octadecyltriethylammonium+
Octadecyltrimethylammonium+
Octadecyltripropylammonium+
Octyltrimethylammonium+
Pentylammonium+
Piperidinium+
Propylammonium+
Pyrilammonium+
Tetrabutylammonium+
Tetradecyltrimethylammonium+
Tetraethylammonium+
Tetramethylammonium+
Tetraisopentylammonium+
Tetrapentylammmonium+
Tetrapropylammonium+
Triethylammonium+
Triethylsulfonium+
Trimethylammonium+
Trimethylhexylammonium+
Trimethylsulfonium+
Tripropylammonium+
34.6
38
33.6
29.5
24.4
42.0
51.8
30.1
23.8
22.6
42.2
47.2
40.5
20.9
29.6
23.0
39.4
58.7
20
16.6
17.9
19.9
17.2
26.5
37
37.2
40.8
24.3
19.5
21.5
32.6
44.9
17.9
17.5
23.4
34.3
36.1
47.23
34.6
51.4
26.1
0.921
1.012
0.895
0.786
0.650
1.118
1.379
0.802
0.634
0.602
1.124
1.257
1.078
0.557
0.788
0.612
1.049
1.563
0.533
0.442
0.477
0.530
0.458
0.706
0.985
0.991
1.086
0.647
0.519
0.573
0.868
1.196
0.477
0.466
0.623
0.913
0.961
1.258
0.921
1.369
0.695
Organic Anions
Acetatep-Anisate1/2Azelate2BenzoateBromoacetateBromobenzoateButyrateChloroacetatem-Chlorobenzoateo-Chlorobenzoate-
40.9
29.0
40.6
32.4
39.2
30
32.6
39.8
31
30.2
1.089
0.772
0.541
0.863
1.044
0.799
0.868
1.060
0.825
0.804
IONIC CONDUCTIVITY AND DIFFUSION AT INFINITE DILUTION (continued)
Ion
1/3Citrate3CrotonateCyanoacetateCyclohexane carboxylate1/2 1,1-Cyclopropanedicarboxylate2DecylsulfateDichloroacetate1/2Diethylbarbiturate2Dihydrogencitrate1/2Dimethylmalonate23,5-DinitrobenzoateDodecylsulfateEthylmalonateEthylsulfateFluoroacetateFluorobenzoateFormate1/2Fumarate21/2Glutarate2HydrogenoxalateIsovalerate-
© 2000 by CRC PRESS LLC
λ
10-4 m2 S mol-1
70.2
33.2
43.4
28.7
53.4
26
38.3
26.3
30
49.4
28.3
24
49.3
39.6
44.4
33
54.6
61.8
52.6
40.2
32.7
D
10-5 cm2 s-1
0.623
0.884
1.156
0.764
0.711
0.692
1.020
0.350
0.799
0.658
0.754
0.639
1.313
1.055
1.182
0.879
1.454
0.823
0.700
1.070
0.871
Ion
IodoacetateLactate1/2Malate21/2Maleate21/2Malonate2MethylsulfateNaphthylacetate1/2Oxalate2OctylsulfatePhenylacetate1/2o-Phthalate21/2m-Phthalate2PicratePivalatePropionatePropylsulfateSalicylate1/2Suberate21/2Succinate2p-Sulfonate
1/2Tartarate2Trichloroacetate-
λ
10-4 m2 S mol-1
D
10-5 cm2 s-1
40.6
38.8
58.8
61.9
63.5
48.8
28.4
74.11
29
30.6
52.3
54.7
30.37
31.9
35.8
37.1
36
36
58.8
29.3
59.6
35
1.081
1.033
0.783
0.824
0.845
1.299
0.756
0.987
0.772
0.815
0.696
0.728
0.809
0.849
0.953
0.988
0.959
0.479
0.783
0.780
0.794
0.932