Appendix J: Solubility Product Constant
Solubility Product Constants for Select Compounds
Ksp determined at 25 °C.
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|
Substance
|
Ksp
|
|---|---|
|
Aluminum Compounds
|
|
|
AlAsO4
|
1.6 × 10−16
|
|
Al(OH)3 amorphous
|
1.3 × 10−33
|
|
AlPO4
|
6.3 × 10−19
|
|
Barium Compounds
|
|
|
Ba3(AsO4)2
|
8.0 × 10−15
|
|
BaCO3
|
5.1 × 10−9
|
|
BaC2O4
|
1.6 × 10−7
|
|
BaCrO4
|
1.2 × 10−10
|
|
BaF2
|
1.0 × 10−6
|
|
Ba(OH)2
|
5 × 10−3
|
|
Ba3(PO4)2
|
3.4 × 10−23
|
|
BaSeO4
|
3.5 × 10−8
|
|
BaSO4
|
1.1 × 10−10
|
|
BaSO3
|
8 × 10−7
|
|
BaS2O3
|
1.6 × 10−5
|
|
Bismuth Compounds
|
|
|
BiAsO4
|
4.4 × 10−10
|
|
BiOCl‡
|
1.8 × 10−31
|
|
BiO(OH)
|
4 × 10−10
|
|
Bi(OH)3
|
4 × 10−31
|
|
BiI3
|
8.1 × 10−19
|
|
BiPO4
|
1.3 × 10−23
|
|
Cadmium Compounds
|
|
|
Cd3(AsO4)2
|
2.2 × 10−33
|
|
CdCO3
|
5.2 × 10−12
|
|
Cd(CN)2
|
1.0 × 10−8
|
|
Cd2[Fe(CN)6]
|
3.2 × 10−17
|
|
Cd(OH)2 fresh
|
2.5 × 10−14
|
|
Calcium Compounds
|
|
|
Ca3(AsO4)2
|
6.8 × 10−19
|
|
CaCO3
|
2.8 × 10−9
|
|
CaCrO4
|
7.1 × 10−4
|
|
CaC2O4·H2O§
|
4 × 10−9
|
|
CaF2
|
5.3 × 10−9
|
|
Ca(OH)2
|
5.5 × 10−6
|
|
CaHPO4
|
1 × 10−7
|
|
Ca3(PO4)2
|
2.0 × 10−29
|
|
CaSeO4
|
8.1 × 10−4
|
|
CaSO4
|
9.1 × 10−6
|
|
CaSO3
|
6.8 × 10−8
|
|
Chromium Compounds
|
|
|
CrAsO4
|
7.7 × 10−21
|
|
Cr(OH)2
|
2 × 10−16
|
|
Cr(OH)3
|
6.3 × 10−31
|
|
CrPO4·4H2O green§
|
2.4 × 10−23
|
|
CrPO4·4H2O violet§
|
1.0 × 10−17
|
|
Cobalt Compounds
|
|
|
Co3(AsO4)2
|
7.6 × 10−29
|
|
CoCO3
|
1.4 × 10−13
|
|
Co(OH)2 fresh
|
1.6 × 10−15
|
|
Co(OH)3
|
1.6 × 10−44
|
|
CoHPO4
|
2 × 10−7
|
|
Co3(PO4)2
|
2 × 10−35
|
|
Copper Compounds
|
|
|
CuBr
|
5.3 × 10−9
|
|
CuCl
|
1.2 × 10−6
|
|
CuCN
|
3.2 × 10−20
|
|
CuI
|
1.1 × 10−12
|
|
CuOH
|
1 × 10−14
|
|
CuSCN
|
4.8 × 10−15
|
|
Cu3(AsO4)2
|
7.6 × 10−36
|
|
CuCO3
|
1.4 × 10−10
|
|
Cu2[Fe(CN)6]
|
1.3 × 10−16
|
|
Cu(OH)2
|
2.2 × 10−20
|
|
Cu3(PO4)2
|
1.3 × 10−37
|
|
Gold Compounds
|
|
|
AuCl
|
2.0 × 10−13
|
|
AuI
|
1.6 × 10−23
|
|
AuCl3
|
3.2 × 10−25
|
|
Au(OH)3
|
5.5 × 10−46
|
|
AuI3
|
1 × 10−46
|
|
Iron Compounds
|
|
|
FeCO3
|
3.2 × 10−11
|
|
Fe(OH)2
|
8.0 × 10−16
|
|
FeC2O4·2H2O§
|
3.2 × 10−7
|
|
FeAsO4
|
5.7 × 10−21
|
|
Fe4[Fe(CN)6]3
|
3.3 × 10−41
|
|
Fe(OH)3
|
4 × 10−38
|
|
FePO4
|
1.3 × 10−22
|
|
Lead Compounds
|
|
|
Pb3(AsO4)2
|
4.0 × 10−36
|
|
PbBr2
|
4.0 × 10−5
|
|
PbCO3
|
7.4 × 10−14
|
|
PbCl2
|
1.6 × 10−5
|
|
PbCrO4
|
2.8 × 10−13
|
|
PbF2
|
2.7 × 10−8
|
|
Pb(OH)2
|
1.2 × 10−15
|
|
PbI2
|
7.1 × 10−9
|
|
PbC2O4
|
4.8 × 10−10
|
|
PbHPO4
|
1.3 × 10−10
|
|
Pb3(PO4)2
|
8.0 × 10−43
|
|
PbSeO4
|
1.4 × 10−7
|
|
PbSO4
|
1.6 × 10−8
|
|
Pb(SCN)2
|
2.0 × 10−5
|
|
Magnesium Compounds
|
|
|
Mg3(AsO4)2
|
2.1 × 10−20
|
|
MgCO3
|
3.5 × 10−8
|
|
MgCO3·3H2O§
|
2.1 × 10−5
|
|
MgC2O4†
|
4.83 × 10−6
|
|
MgF2
|
6.5 × 10−9
|
|
Mg(OH)2
|
1.8 × 10−11
|
|
Mg3(PO4)2
|
10−23 to 10−27
|
|
MgSeO3
|
1.3 × 10−5
|
|
MgSO3
|
3.2 × 10−3
|
|
MgNH4PO4
|
2.5 × 10−13
|
|
Manganese Compounds
|
|
|
Mn3(AsO4)2
|
1.9 × 10−29
|
|
MnCO3
|
1.8 × 10−11
|
|
Mn2[Fe(CN)6]
|
8.0 × 10−13
|
|
Mn(OH)2
|
1.9 × 10−13
|
|
MnC2O4·2H2O§
|
1.1 × 10−15
|
|
Mercury Compounds
|
|
|
Hg2Br2
|
5.6 × 10−23
|
|
Hg2CO3
|
8.9 × 10−17
|
|
Hg2(CN)2
|
5 × 10−40
|
|
Hg2Cl2
|
1.3 × 10−18
|
|
Hg2CrO4
|
2.0 × 10−9
|
|
Hg(OH)2
|
2.0 × 10−24
|
|
Hg2I2
|
4.5 × 10−29
|
|
Hg2SO4
|
7.4 × 10−7
|
|
Hg2SO3
|
1.0 × 10−27
|
|
Hg2(OH)2
|
2.0 × 10−24
|
|
Hg(OH)2
|
3.0 × 10−26
|
|
Nickel Compounds
|
|
|
Ni3(AsO4)2
|
3.1 × 10−26
|
|
NiCO3
|
6.6 × 10−9
|
|
2 Ni(CN)2 ⇌ Ni2+ + Ni(CN)42−
|
1.7 × 10−9
|
|
Ni2[Fe(CN)6]
|
1.3 × 10−15
|
|
Ni(OH)2 fresh
|
2.0 × 10−15
|
|
NiC2O4
|
4 × 10−10
|
|
Ni3(PO4)2
|
5 × 10−31
|
|
Silver Compounds
|
|
|
Ag3AsO4
|
1.0 × 10−22
|
|
AgBr
|
5.0 × 10−13
|
|
Ag2CO3
|
8.1 × 10−12
|
|
AgCl
|
1.8 × 10−10
|
|
Ag2CrO4
|
1.1 × 10−12
|
|
AgCN
|
1.2 × 10−16
|
|
Ag2Cr2O7
|
2.0 × 10−7
|
|
Ag4[Fe(CN)6]
|
1.6 × 10−41
|
|
AgOH
|
2.0 × 10−8
|
|
AgI
|
8.3 × 10−17
|
|
Ag3PO4
|
1.4 × 10−16
|
|
Ag2SO4
|
1.4 × 10−5
|
|
Ag2SO3
|
1.5 × 10−14
|
|
AgSCN
|
1.0 × 10−12
|
|
Strontium Compounds
|
|
|
Sr3(AsO4)2
|
8.1 × 10−19
|
|
SrCO3
|
1.1 × 10−10
|
|
SrCrO4
|
2.2 × 10−5
|
|
SrC2O4·H2O§
|
1.6 × 10−7
|
|
Sr3(PO4)2
|
4.0 × 10−28
|
|
SrSO4
|
3.2 × 10−7
|
|
SrSO3
|
4 × 10−8
|
|
Tin Compounds
|
|
|
Sn(OH)2
|
1.4 × 10−28
|
|
Sn(OH)4
|
1 × 10−56
|
|
Zinc Compounds
|
|
|
Zn3(AsO4)2
|
1.3 × 10−28
|
|
ZnCO3
|
1.4 × 10−11
|
|
Zn2[Fe(CN)6]
|
4.0 × 10−16
|
|
Zn(OH)2
|
1.2 × 10−17
|
|
ZnC2O4
|
2.7 × 10−8
|
|
Zn3(PO4)2
|
9.0 × 10−33
|
| From Patnaik, P., Dean's Analytical Chemistry Handbook, 2nd ed. New York: McGraw-Hill, 2004, Table 4.2. No metal sulfides are listed in this table because sulfide ion is such a strong base that the usual solubility product equilibrium equation does not apply. See Myers, R. J. Journal of Chemical Education, Vol. 63, 1986, pp. 687-690. ‡From Meites, L. Ed. Handbook of Analytical Chemistry, 1st ed. New York: McGraw-Hill, 1963. §Because [H2O] does not appear in equilibrium constants for equilibria in aqueous solution in general, it does not appear in the Ksp expressions for hydrated solids. †From "Solubility Product Constants of Inorganic Salts," in CRC Handbook of Chemistry and Physics, 101st Edition (Internet Version 2020), John R. Rumble, ed., CRC Press/Taylor & Francis, Boca Raton, FL. |
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