Solubility Products at 25<sup>o</sup>C

Selected Solubility Products and Formation Constants at 25oC
Solubility Rules

Although all compounds have a characteristic solubility in water at a given temperature, some families of compounds are more soluble than others and it is useful to know certain general rules of solubility. We call any substance the solubility of which is less than 0.01 mol/L insoluble. If its solubility is greater than 0.1 mol/L, we call it soluble. If its solubility is between 0.01 and 0.1 mol/L, we say that it is slightly soluble. The following solubility rules can be used to determine solubilities in water, with the disclaimer that they don't always hold, nor do they include every ion which is in common use, but they are good to have nearby when needed:

1. All sodium, potassium, and ammonium salts are soluble.
2. All nitrates, acetates and perchlorates are soluble.
3. All silver, lead and mercury(I) salts are insoluble.
4. All chlorides, bromides and iodides are soluble.
5. All carbonates, sulfides, oxides and hydroxides are insoluble.
6. All sulfates are soluble except strontium sulfate and barium sulfate.

That having been said, here is a table of solubility product constants.

Compound Formula Ksp
aluminum hydroxide Al(OH)3 4.6 x 10-33
aluminum phosphate AlPO4 6.3 x 10-19
barium carbonate BaCO3 5.1 x 10-9
barium chromate BaCrO4 2.2 x 10-10
barium fluoride BaF2 1.0 x 10-6
barium hydroxide Ba(OH)2 5 x 10-3
barium iodate Ba(IO3)2 1.5 x 10-9
barium oxalate BaC2O4 2.3 x 10-8
barium sulfate BaSO4 1.1 x 10-10
barium sulfite BaSO3 8 x 10-7
barium thiosulfate BaS2O3 1.6 10-5
bismuthyl chloride BiOCl 1.8 x 10-31
bismuthyl hydroxide BiOOH 4 x 10-10
bismuth(III) sulfide Bi2S3 1 x 10-97
cadmium carbonate CdCO3 5.2 x 10-12
cadmium hydroxide Cd(OH)2 2.5 x 10-14
cadmium iodate Cd(IO3)2 2.3 x 10-8
cadmium sulfide CdS 8.0 x 10-27
calcium carbonate CaCO3 3.8 x 10-9
calcium chromate CaCrO4 7.1 x 10-4
calcium fluoride CaF2 5.3 x 10-9
calcium hydroxide Ca(OH)2 5.5 x 10-6
calcium iodate Ca(IO3)2 7.1 x 10-7
calcium oxalate hydrate CaC2O4.H2O 1.96 x 10-8
calcium hydrogen phosphate CaHPO4 1 x 10-7
calcium phosphate Ca3(PO4)2 1 x 10-26
calcium sulfate CaSO4 9.1 x 10-6
calcium sulfite CaSO3 6.8 x 10-8
chromium(II) hydroxide Cr(OH)2 2 x 10-16
chromium(III) hydroxide Cr(OH)3 6.3 x 10-31
cobalt(II) carbonate CoCO3 1.4 x 10-13
cobalt(III) hydroxide Co(OH)3 1.6 x 10-44
cobalt(II) sulfide CoS 4.0 x 10-21
copper(I) chloride CuCl 1.2 x 10-6
copper(I) cyanide CuCN 3.2 x 10-20
copper(I) iodide CuI 1.1 x 10-12
copper(I) sulfide Cu2S 2.5 x 10-48
copper(II) arsenate Cu3(AsO4)2 7.6 x 10-36
copper(II) carbonate CuCO3 1.4 x 10-10
copper(II) chromate CuCrO4 3.6 x 10-6
copper(II) ferrocyanide Cu2[Fe(CN)6] 1.3 x 10-16
copper(II) hydroxide Cu(OH)2 2.2 x 10-20
copper(II) sulfide CuS 6 x 10-37
copper(II) thiocyanate Cu(SCN)2 4.0 x 10-14
fluorapatite Ca5(PO4)3F 1.0 x 10-60
hydroxyapatite Ca5(PO4)3OH 1.0 x 10-36
iron(II) carbonate FeCO3 3.2 x 10-11
iron(II) hydroxide Fe(OH)2 8.0 x 10-16
iron(II) sulfide FeS 6 x 10-19
iron(III) arsenate FeAsO4 5.7 x 10-21
iron(III) ferrocyanide Fe4[Fe(CN)6]3 3.3 x 10-41
iron(III) hydroxide Fe(OH)3 4 x 10-38
iron(III) phosphate FePO4 1.3 x 10-22
lead(II) arsenate Pb3(AsO4)2 4.0 x 10-36
lead(II) azide Pb(N3)2 2.5 x 10-9
lead(II) bromate Pb(BrO3)2 7.9 x 10-6
lead(II) bromide PbBr2 4.0 x 10-5
lead(II) carbonate PbCO3 7.4 x 10-14
lead(II) chloride PbCl2 1.6 x 10-5
lead(II) chromate PbCrO4 2.8 x 10-13
lead(II) fluoride PbF2 2.7 x 10-8
lead(II) hydroxide Pb(OH)2 1.2 x 10-5
lead(II) iodate Pb(IO3)2 2.6 x 10-13
lead(II) iodide PbI2 7.1 x 10-9
lead(II) sulfate PbSO4 1.6 x 10-8
lead(II) sulfide PbS 3 x 10-29
lithium carbonate Li2CO3 2.5 x 10-2
lithium fluoride LiF 3.8 x 10-3
lithium phosphate Li3PO4 3.2 x 10-9
magnesium ammonium phosphate MgNH4PO4 2.5 x 10-13
magnesium arsenate Mg3(AsO4)2 2.1 x 10-20
magnesium carbonate MgCO3 3.5 x 10-8
magnesium fluoride MgF2 3.7 x 10-8
magnesium hydroxide Mg(OH)2 1.8 x 10-11
magnesium oxalate MgC2O4 7 x 10-7
magnesium phosphate Mg3(PO4)2 1 x 10-25
manganese(II) carbonate MnCO3 1.8 x 10-11
manganese(II) hydroxide Mn(OH)2 1.9 x 10-9
manganese(II) sulfide MnS 2.5 x 10-13
mercury(I) bromide Hg2Br2 5.6 x 10-23
mercury(I) chloride Hg2Cl2 5.0 x 10-13
mercury(I) chromate Hg2CrO4 2.0 x 10-9
mercury(I) cyanide Hg2(CN)2 5 x 10-40
mercury(I) iodide HgI2 4.5 x 10-29
mercury(I) sulfate Hg2SO4 7.4 x 10-7
mercury(I) sulfide Hg2S 1.0 x 10-47
mercury(I) thiocyanate Hg2(SCN)2 3.0 x 10-20
mercury(II) sulfide HgS 1.6 x 10-52
mercury(II) thiocyanate Hg(SCN)2 2.8 x 10-20
nickel(II) carbonate NiCO3 6.6 x 10-9
nickel(II) hydroxide Ni(OH)2 2.0 x 10-15
nickel(II) sulfide NiS 3 x 10-19
scandium fluoride ScF3 4.2 x 10-18
scandium hydroxide Sc(OH)3 4.2 x 10-18
silver arsenate Ag3AsO4 1.0 x 10-22
silver acetate AgC2H3O2 2.0 x 10-3
silver azide AgN3 2.0 x 10-8
silver benzoate AgC7H5O2 2.5 x 10-5
silver bromate AgBrO3 5.5 x 10-5
silver bromide AgBr 5.3 x 10-13
silver carbonate Ag2CO3 8.1 x 10-12
silver chloride AgCl 1.8 x 10-10
silver chromate Ag2CrO4 1.1 x 10-12
silver cyanide AgCN 1.2 x 10-16
silver iodate AgIO3 3.0 x 10-8
silver iodide AgI 8.3 x 10-17
silver nitrite AgNO2 6.0 x 10-4
silver oxalate Ag2C2O4 3.6 x 10-11
silver sulfate Ag2SO4 1.4 x 10-5
silver sulfide Ag2S 6 x 10-51
silver sulfite AgSO3 1.5 x 10-14
silver thiocyanate AgSCN 1.0 x 10-12
strontium carbonate SrCO3 1.1 x 10-10
strontium chromate SrCrO4 2.2 x 10-5
strontium fluoride SrF2 2.5 x 10-9
strontium oxalate SrC2O4 4 x 10-7
strontium sulfate SrSO4 3.2 x 10-7
strontium sulfite SrSO3 4 x 10-8
thallium(I) bromate TlBrO3 1.7 x 10-4
thallium(I) bromide TlBr 3.4 x 10-6
thallium(I) chloride TlCl 1.7 x 10-4
thallium(I) chromate Tl2CrO4 9.8 x 10-15
thallium(I) iodate TlIO3 3.1 x 10-6
thallium(I) iodide TlI 6.5 x 10-8
thallium(I) sulfide Tl2S 6 x 10-22
thallium(I) thiocyante TlSCN 1.6 x 10-4
thallium(III) hydroxide Tl(OH)3 6.3 x 10-46
tin(II) hydroxide Sn(OH)2 1.4 x 10-28
tin(II) sulfide SnS 1 x 10-26
zinc carbonate ZnCO3 1.4 x 10-11
zinc cyanide Zn(CN)2 3 x 10-16
zinc hydroxide Zn(OH)2 1.2 x 10-17
zinc iodate Zn(IO3)2 3.9 x 10-6
zinc oxalate ZnC2O4 2.7 x 10-8
zinc phosphate Zn3(PO4)2 9.0 x 10-33
zinc sulfide ZnS 2 x 10-25
Formation Constants of Selected Complex Ions, at 25oC Formula Kf
Ag(CN)2- 5.6 x 1018
Ag(NH3)2+ 1.7 x 107
Ag(S2O3)23- 2.9 x 1013
Co(SCN)+ 100
Cu(CN)2- 1.0 x 1016
Cu(NH3)42+ 1.0 x 1013
Fe(SCN)2+ 900
HgI42- 4.2 x 1027
Zn(NH3)42+ 2.9 x 109
Zn(OH)42- 4.6 x 1017