Table of Solubility Products for Some Sparingly Soluble Salts at 25°C

Submitted by ChemPRIME Staff on Thu, 12/09/2010 - 14:25

APPENDIX H


Solubility ProductThe equilibrium constant expression for the dissolution of an electrolyte; the reactant is a solid and its concentration does not appear in the expression, which is a product of the concentrations of the products (raised the to appropriate powers). Constants for Some InorganicPertaining to the chemistry of elements other than carbon and compounds containing at most a small amount of carbon. Compounds at 25 °C1

Substance Ksp Substance Ksp
Aluminum Compounds Barium Compounds
AlAsO4 1.6 × 10-16 Ba3(AsO4)2 8.0 × 10-15
Al(OH)3 amorphous 1.3 × 10-33 BaCO3 5.1 × 10-9
AlPO4 6.3 × 10-19 BaC2O4 1.6 × 10-7
Bismuth Compounds BaCrO4 1.2 × 10-10
BiAsO4 4.4 ×10-10 BaF2 1.0 × 10-6
BiOCl2 7.0 × 10-9 Ba(OH)2 5 × 10-3
BiO(OH) 4 × 10-10 Ba3(PO4)2 3.4 × 10-23
Bi(OH)3 4 ×10-31 BaSeO4 3.5 × 10-8
Bil3 8.1 ×10-19 BaSO4 1.1 × 10-10
BiPO4 1.3 ×10-23 BaSO3 8 × 10-7
Cadmium Compounds BaS2O3 1.6 × 10-5
Cd3(AsO4)2 2.2 ×10-33 Calcium Compounds
CdCO3 5.2 ×10-12 Ca3(AsO4)2 6.8 ×10-19
Cd(CN)2 1.0 ×10-8 CaCO3 2.8 ×10-9
Cd2[Fe(CN)6] 3.2 ×10-17 CaCrO4 7.1 ×10-4
Cd(OH)2 fresh 2.5 ×10-14 CaC2O4 • H2O3 4 × 10-9
Chromium Compounds CaF2 5.3 ×10-9
CrAsO4 7.7 × 10-21 Ca(OH)2 5.5 ×10-6
Cr(OH)2 2 × 10-16 CaHPO4 1 × 10-7
Cr(OH)3 6.3 × 10-31 Ca3(PO4)2 2.0 × 10-29
CrPO4 • 4H2O green 2.4 × 10-23 CaSeO4 8.1 × 10-4
CrPO4 • 4H2O violet 1.0 × 10-17 CaSO4 9.1 × 10-6
Cobalt Compounds CaSO3 6.8 × 10-8
Co3(AsO4)2 7.6 × 10-29 Copper Compounds
CoCO3 1.4 × 10-13 CuBr 5.3 × 10-9
Co(OH)2 fresh 1.6 × 10-15 CuCl 1.2 × 10-6
Co(OH)3 1.6 × 10-44 CuCN 3.2 × 10-20
CoHPO4 2 × 10-7 CuI 1.1 × 10-12
CO3(PO4)2 2 × 10-35 CuOH 1 × 10-14
Gold Compounds CuSCN 4.8 × 10-15
AuCl 2.0 × 10-13 Cu3(AsO4)2 7.6 × 10-36
AuI 1.6 × 10-23 CuCO3 1.4 × 10-10
AuCl3 3.2 × 10-25 Cu2[Fe(CN)6] 1.3 × 10-16
Au(OH)3 5.5 × 10-46 Cu(OH)2 2.2 × 10-20
AuI3 1 × 10-46 Cu3(PO4)2 1.3 × 10-37
Iron Compounds Lead Compounds
FeCO3 3.2 × 10-11 Pb3(AsO4)2 4.0 × 10-36
Fe(OH)2 8.0 × 10-16 PbBr2 4.0 × 10-5
FeC2O4 • 2H2O3 3.2 × 10-7 PbCO3 7.4 × 10-14
FeAsO4 5.7 × 10-21 PbCl2 1.6 × 10-5
Fe4[Fe(CN)6]3 3.3 × 10-41 PbCrO4 2.8 × 10-13
Fe(OH)3 4 × 10-38 PbF2 2.7 × 10-8
FePO4 1.3 × 10-22 Pb(OH)2 1.2 × 10-15
Magnesium Compounds PbI2 7.1 × 10-9
Mg3(AsO4)2 2.1 × 10-20 PbC2O4 4.8 × 10-10
MgCO3 3.5 × 10-8 PbHPO4 1.3 × 10-10
MgCO3 • 3H2O3 2.1 × 10-5 Pb3(PO4)2 8.0 × 10-43
MgC2O4 • 2H2O3 1 × 10-8 PbSeO4 1.4 × 10-7
MgF2 6.5 × 10-9 PbSO4 1.6 × 10-8
Mg(OH)2 1.8 × 10-11 Pb(SCN)2 2.0 × 10-5
Mg3(PO4)2 10-23 to 10-27 Manganese Compounds
MgSeO3 1.3 × 10-5 Mn3(AsO4)2 1.9 × 10-29
MgSO3 3.2 × 10-3 MnCO3 1.8 × 10-11
MgNH4PO4 2.5 × 10-13 Mn2[Fe(CN)6] 8.0 × 10-13
Mercury Compounds Mn(OH)2 1.9 × 10-13
Hg2Br2 5.6 × 10-23 MnC2O4 • 2H2O3 1.1 × 10-15
Hg2CO3 8.9 × 10-17 Nickel Compounds
Hg2(CN)2 5 × 10-40 Ni3(AsO4)2 3.1 × 10-26
Hg2Cl2 1.3 × 10-18 NiCO3 6.6 × 10-9
Hg2CrO4 2.0 × 10-9 2 Ni(CN)2 → Ni2+ + Ni(CN)42 1.7 × 10-9
Hg2(OH)2 2.0 × 10-24 Ni2[Fe(CN)6] 1.3 × 10-15
Hg2l2 4.5 × 10-29 Ni(OH)2 fresh 2.0 × 10-15
Hg2SO4 7.4 × 10-7 NiC2O4 4 × 10-10
Hg2SO3 1.0 × 10-27 Ni3(PO4)2 5 × 10-31
Hg(OH)2 3.0 × 10-26 Silver Compounds
Strontium Compounds Ag3AsO4 1.0 × 10-22
Sr3(AsO4)2 8.1 × 10-19 AgBr 5.0 × 10-13
SrCO3 1.1 × 10-10 Ag2CO3 8.1 × 10-12
SrCrO4 2.2 × 10-5 AgCl 1.8 × 10-10
SrC2O4 • H2O3 1.6 × 10-7 Ag2CrO4 1.1 × 10-12
Sr3(PO4)2 4.0 × 10-28 AgCN 1.2 × 10-16
SrSO3 4 × 10-8 Ag2Cr2O7 2.0 × 10-7
SrSO4 3.2 × 10-7 Ag4[Fe(CN)6] 1.6 × 10-41
Tin Compounds AgOH 2.0 × 10-8
Sn(OH)2 1.4 × 10-28 AgI 8.3 × 10-17
Sn(OH)4 1 × 10-56 Ag3PO4 1.4 × 10-16
Zinc Compounds Ag2SO4 1.4 × 10-5
Zn3(AsO4)2 1.3 × 10-28 Ag2SO3 1.5 × 10-14
ZnCO3 1.4 × 10-11 AgSCN 1.0 × 10-12
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


1. Taken from Patnaik, Pradyot, Dean’s Analytical Chemistry Handbook, 2nd ed., New York: McGraw-Hill, 2004, Table 4.2 (published on the Web by Knovel, http://www.knovel.com).

2. Taken from Meites, L. ed., Handbook of Analytical Chemistry, 1st ed., New York: McGraw-Hill, 1963.

3. Because [H2O] does not appear in equilibrium constants for equilibria in aqueousDescribing a solution in which the solvent is water. solutionA mixture of one or more substances dissolved in a solvent to give a homogeneous mixture. in general, it does not appear in the Ksp expressions for hydrated solids.


No metalAn element characterized by a glossy surface, high thermal and electrical conductivity, malleability, and ductility. sulfides are listed in this table because sulfide ion is such a strong baseA base that dissociates completely or ionizes completely in a particular solvent. that the usual solubilityThe extent to which a solute dissolves in a solvent; often expressed as the mass of a substance that will dissolve in 100 mL of solvent. product equilibriumA state in which no net change is occurring, that is, in which the concentrations of reactants and products remain constant; chemical equilibrium is characterized by forward and reverse reactions occurring at the same rate. equation does not apply. See Myers, R. J. Journal of Chemical Education, Vol. 63, 1986; pp. 687-690.


The above table gives Ksp values for a number of salts that are largely insolubleUnable to dissolve appreciably in a solvent. in aqueous solution, and defines how much of the salt will dissolve. For a general case of such a salt, an equilibrium process can be defined as:

AxBy(s) \rightleftharpoons xAm+(aq) + yBn+(aq)

From this process, the Ksp can be defined as:

Ksp = [Am+]x[ Bn+]y

General solubility rules for ionic compounds are shown below:

Soluble in Water Important Exceptions (insoluble)
All Group IA and NH4+ salts
All nitrates, chlorates, perchlorates and acetates
All sulfates CaSO4, BaSO4, SrSO4, PbSO4
All chlorides, bromides, and iodides AgX, Hg2X2, PbX2 (X= Cl, Br, or I)
Sparingly Soluble in Water Important Exceptions (soluble)
All carbonates and phosphates Group IA and NH4+ salts
All hydroxides Group IA and NH4+ salts; Ba2+, Sr2+, Ca2+ sparingly soluble
All sulfides Group IA, IIA and NH4+ salts; MgS, CaS, BaS sparingly soluble
All oxalates Group IA and NH4+ salts
The following electrolytes are of only moderate solubility in water:
CH3COOAg, Ag2SO4, KClO4
They will precipitate only if rather concentrated solutions are used


More information on Solubility Products can be found on CoreChem:The Solubility Product.