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Appendix 10: Solubility Products

  • Page ID
    6646
  • The following table provides pKsp and Ksp values for selected compounds, organized by the anion. All values are from Martell, A. E.; Smith, R. M. Critical Stability Constants, Vol. 4. Plenum Press: New York, 1976. Unless otherwise stated, values are for 25 oC and zero ionic strength.

    Bromide (Br)

    pKsp

    Ksp

    CuBr

    8.3

    5.×10–9

    AgBr

    12.30

    5.0×10–13

    Hg2Br2

    22.25

    5.6×10–13

    HgBr2 (μ = 0.5 M)

    18.9

    1.3×10–19

    PbBr2 (μ = 4.0 M)

    5.68 2.1×10–6

    Carbonate (CO32–)

    pKsp

    Ksp

    MgCO3

    7.46

    3.5×10–8

    CaCO3 (calcite)

    8.35

    4.5×10–9

    CaCO3 (aragonite)

    8.22

    6.0×10–9

    SrCO3

    9.03

    9.3×10–10

    BaCO3

    8.30

    5.0×10–9

    MnCO3

    9.30

    5.0×10–10

    FeCO3

    10.68

    2.1×10–11

    CoCO3

    9.98

    1.0×10–10

    NiCO3

    6.87

    1.3×10–7

    Ag2CO3

    11.09

    8.1×10–12

    Hg2CO3

    16.05

    8.9×10–17

    ZnCO3

    10.00

    1.0×10–10

    CdCO3

    13.74

    1.8×10–14

    PbCO3 13.13

    7.4×10–14

    Chloride (Cl)

    pKsp

    Ksp

    CuCl

    6.73

    1.9×10–7

    AgCl

    9.74

    1.8×10–10

    Hg2Cl2

    17.91

    1.2×10–18

    PbCl2

    4.78

    2.0×10–19

    Chromate (CrO42–)

    pKsp

    Ksp

    BaCrO4

    9.67

    2.1×10–10

    CuCrO4

    5.44

    3.6×10–6

    Ag2CrO4

    11.92

    1.2×10–12

    Hg2CrO4

    8.70

    2.0×10–9

    Cyanide (CN)

    pKsp

    Ksp

    AgCN

    15.66

    2.2×10–16

    Zn(CN)2 (μ = 3.0 M)

    15.5

    3.×10–16

    Hg2(CN)2

    39.3

    5.×10–40

    Ferrocyanide [Fe(CN)64–]

    pKsp

    Ksp

    Zn2[Fe(CN)6]

    15.68

    2.1×10–16

    Cd2[Fe(CN)6]

    17.38

    4.2×10–18

    Pb2[Fe(CN)6]

    18.02

    9.5×10–19

    Fluoride (F)

    pKsp

    Ksp

    MgF2

    8.18

    6.6×10–9

    CaF2

    10.41

    3.9×10–11

    SrF2

    8.54

    2.9×10–9

    BaF2

    5.76

    1.7×10–6

    PbF2 7.44

    3.6×10–8

    Hydroxide (OH)

    pKsp

    Ksp

    Mg(OH)2

    11.15

    7.1×10–12

    Ca(OH)2

    5.19

    6.5×10–6

    Ba(OH)2•8H2O

    3.6

    3.×10–4

    La(OH)3

    20.7

    2.×10–21

    Mn(OH)2

    12.8

    1.6×10–13

    Fe(OH)2

    15.1

    8.×10–16

    Co(OH)2

    14.9

    1.3×10–15

    Ni(OH)2

    15.2

    6.×10–16

    Cu(OH)2

    19.32

    4.8×10–20

    Fe(OH)3

    38.8

    1.6×10–39

    Co(OH)3 (T = 19oC)

    44.5

    3.×10–45

    Ag2O (+ H2O ⇋ 2Ag+ + 2OH)

    15.42

    3.8×10–16

    Cu2O (+ H2O ⇋ 2Cu+ + 2OH) 29.4 4.×10–30
    Zn(OH)2 (amorphous) 15.52 3.0×10–16
    Cd(OH)2 (β) 14.35 4.5×10–15
    HgO (red) (+ H2O ⇋ Hg2+ + 2OH) 25.44 3.6×10–26
    SnO (+ H2O ⇋ Sn2+ + 2OH) 26.2 6.×10–27
    PbO (yellow) (+ H2O ⇋ Pb2+ + 2OH) 15.1 8.×10–16
    Al(OH)3 (α) 33.5 3.×10–34

    Iodate (IO3)

    pKsp

    Ksp

    Ca(IO3)2

    6.15

    7.1×10–7

    Ba(IO3)2

    8.81

    1.5×10–9

    AgIO3

    7.51

    3.1×10–8

    Hg2(IO3)2

    17.89

    1.3×10–18

    Zn(IO3)2

    5.41

    3.9×10–6

    Cd(IO3)2

    7.64

    2.3×10–8

    Pb(IO3)2

    12.61 2.5×10–13

    Iodide (I)

    pKsp

    Ksp

    AgI

    16.08

    8.3×10–17

    Hg2I2

    28.33

    4.7×10–29

    HgI2 (μ = 0.5 M)

    27.95

    1.1×10–28

    PbI2

    8.10 7.9×10–9

    Oxalate (C2O42–)

    pKsp Ksp

    CaC2O4 (μ = 0.1 M, T = 20 oC)

    7.9

    1.3×10–8

    BaC2O4 (μ = 0.1 M, T = 20 oC)

    6.0

    1.×10–6

    SrC2O4 (μ = 0.1 M, T = 20 oC)

    6.4 4.×10–7

    Phosphate (PO43–)

    pKsp

    Ksp

    Fe3(PO4)2•8H2O

    36.0

    1.×10–36

    Zn3(PO4)2•4H2O

    35.3

    5.×10–36

    Ag3PO4

    17.55

    2.8×10–18

    Pb3(PO4)2 (T = 38 oC)

    43.55

    3.0×10–44

    Sulfate (SO42–)

    pKsp

    Ksp

    CaSO4

    4.62

    2.4×10–5

    SrSO4

    6.50

    3.2×10–7

    BaSO4

    9.96

    1.1×10–10

    Ag2SO4

    4.83

    1.5×10–5

    Hg2SO4

    6.13

    7.4×10–7

    PbSO4

    7.79

    1.6×10–8

    Sulfide (S2–)

    pKsp Ksp

    MnS (green)

    13.5

    3.×10–14

    FeS

    18.1

    8.×10–19

    CoS (β)

    25.6

    3.×10–26

    NiS (γ)

    26.6

    3.×10–27

    CuS

    36.1

    8.×10–37

    Cu2S

    48.5

    3.×10–49

    Ag2S

    50.1

    8.×10–51

    ZnS (α)

    24.7

    2.×10–25

    CdS

    27.0

    1.×10–27

    Hg2S (red)

    53.3

    5.×10–54

    PbS

    27.5

    3.×10–28

    Thiocyanate (SCN)

    pKsp Ksp

    CuSCN (μ = 5.0 M)

    13.40

    4.0×10–14

    AgSCN

    11.97

    1.1×10–12

    Hg2(SCN)2

    19.52

    3.0×10–20

    Hg(SCN)2 (μ = 1.0 M)

    19.56

    2.8×10–20

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