Solubility Product Constants (Ksp) at 25 °C
Solubility product constants (Ksp) at 25 °C for 100 sparingly soluble ionic compounds, grouped by metal, each with its dissolution equilibrium. Use Ksp with the dissolution stoichiometry to compute molar solubility, predict precipitation with Q vs Ksp, and analyze common-ion and complex-ion effects.
| Formula | Name | Ksp (25 °C) | Dissolution Equilibrium | Metal |
|---|---|---|---|---|
| Al(OH)3 | Aluminum hydroxide | 4.6 × 10-33 | Al(OH)3(s) ⇌ Al3+(aq) + 3 OH-(aq) | Aluminum |
| Ba(OH)2·8H2O | Barium hydroxide octahydrate | 5.0 × 10-3 | Ba(OH)2·8H2O(s) ⇌ Ba2+(aq) + 2 OH-(aq) + 8 H2O(l) | Barium |
| Ba3(AsO4)2 | Barium arsenate | 1.1 × 10-13 | Ba3(AsO4)2(s) ⇌ 3 Ba2+(aq) + 2 AsO43-(aq) | Barium |
| Ba3(PO4)2 | Barium phosphate | 6 × 10-39 | Ba3(PO4)2(s) ⇌ 3 Ba2+(aq) + 2 PO43-(aq) | Barium |
| BaC2O4·2H2O | Barium oxalate dihydrate | 1.1 × 10-7 | BaC2O4·2H2O(s) ⇌ Ba2+(aq) + C2O42-(aq) + 2 H2O(l) | Barium |
| BaCO3 | Barium carbonate | 1.6 × 10-9 | BaCO3(s) ⇌ Ba2+(aq) + CO32-(aq) | Barium |
| BaCrO4 | Barium chromate | 8.5 × 10-11 | BaCrO4(s) ⇌ Ba2+(aq) + CrO42-(aq) | Barium |
| BaF2 | Barium fluoride | 2.4 × 10-5 | BaF2(s) ⇌ Ba2+(aq) + 2 F-(aq) | Barium |
| BaSO4 | Barium sulfate | 1.1 × 10-10 | BaSO4(s) ⇌ Ba2+(aq) + SO42-(aq) | Barium |
| Bi2S3 | Bismuth sulfide | 1 × 10-97 | Bi2S3(s) ⇌ 2 Bi3+(aq) + 3 S2-(aq) | Bismuth |
| BiO(OH) | Bismuthyl hydroxide | 4 × 10-10 | BiO(OH)(s) ⇌ BiO+(aq) + OH-(aq) | Bismuth |
| BiOCl | Bismuthyl chloride | 1.8 × 10-31 | BiOCl(s) ⇌ BiO+(aq) + Cl-(aq) | Bismuth |
| Cd(OH)2 | Cadmium hydroxide | 5.9 × 10-15 | Cd(OH)2(s) ⇌ Cd2+(aq) + 2 OH-(aq) | Cadmium |
| CdCO3 | Cadmium carbonate | 5.2 × 10-12 | CdCO3(s) ⇌ Cd2+(aq) + CO32-(aq) | Cadmium |
| CdS | Cadmium sulfide | 1.0 × 10-28 | CdS(s) ⇌ Cd2+(aq) + S2-(aq) | Cadmium |
| Ca(OH)2 | Calcium hydroxide | 1.3 × 10-6 | Ca(OH)2(s) ⇌ Ca2+(aq) + 2 OH-(aq) | Calcium |
| Ca3(PO4)2 | Calcium phosphate | 1.3 × 10-32 | Ca3(PO4)2(s) ⇌ 3 Ca2+(aq) + 2 PO43-(aq) | Calcium |
| CaC2O4·H2O | Calcium oxalate monohydrate | 1.96 × 10-9 | CaC2O4·H2O(s) ⇌ Ca2+(aq) + C2O42-(aq) + H2O(l) | Calcium |
| CaCO3 | Calcium carbonate | 3.8 × 10-9 | CaCO3(s) ⇌ Ca2+(aq) + CO32-(aq) | Calcium |
| CaF2 | Calcium fluoride | 3.9 × 10-11 | CaF2(s) ⇌ Ca2+(aq) + 2 F-(aq) | Calcium |
| CaHPO4 | Calcium hydrogen phosphate | 7 × 10-7 | CaHPO4(s) ⇌ Ca2+(aq) + HPO42-(aq) | Calcium |
| CaSO4·2H2O | Calcium sulfate dihydrate | 6.1 × 10-5 | CaSO4·2H2O(s) ⇌ Ca2+(aq) + SO42-(aq) + 2 H2O(l) | Calcium |
| Cr(OH)3 | Chromium(III) hydroxide | 6.7 × 10-31 | Cr(OH)3(s) ⇌ Cr3+(aq) + 3 OH-(aq) | Chromium |
| Co(OH)2 | Cobalt(II) hydroxide | 2.5 × 10-16 | Co(OH)2(s) ⇌ Co2+(aq) + 2 OH-(aq) | Cobalt |
| Co(OH)3 | Cobalt(III) hydroxide | 2.5 × 10-43 | Co(OH)3(s) ⇌ Co3+(aq) + 3 OH-(aq) | Cobalt |
| CoCO3 | Cobalt(II) carbonate | 1.4 × 10-13 | CoCO3(s) ⇌ Co2+(aq) + CO32-(aq) | Cobalt |
| CoS(α) | Cobalt(II) sulfide (alpha form) | 5 × 10-22 | CoS(α)(s) ⇌ Co2+(aq) + S2-(aq) | Cobalt |
| CoS(β) | Cobalt(II) sulfide (beta form) | 3 × 10-26 | CoS(β)(s) ⇌ Co2+(aq) + S2-(aq) | Cobalt |
| Cu(OH)2 | Copper(II) hydroxide | 2.2 × 10-20 | Cu(OH)2(s) ⇌ Cu2+(aq) + 2 OH-(aq) | Copper |
| Cu2S | Copper(I) sulfide | 2.5 × 10-48 | Cu2S(s) ⇌ 2 Cu+(aq) + S2-(aq) | Copper |
| CuBr | Copper(I) bromide | 6.27 × 10-9 | CuBr(s) ⇌ Cu+(aq) + Br-(aq) | Copper |
| CuCl | Copper(I) chloride | 1.2 × 10-6 | CuCl(s) ⇌ Cu+(aq) + Cl-(aq) | Copper |
| CuCO3 | Copper(II) carbonate | 2.5 × 10-10 | CuCO3(s) ⇌ Cu2+(aq) + CO32-(aq) | Copper |
| CuI | Copper(I) iodide | 1.27 × 10-12 | CuI(s) ⇌ Cu+(aq) + I-(aq) | Copper |
| CuS | Copper(II) sulfide | 8.5 × 10-45 | CuS(s) ⇌ Cu2+(aq) + S2-(aq) | Copper |
| CuSCN | Copper(I) thiocyanate | 1.6 × 10-11 | CuSCN(s) ⇌ Cu+(aq) + SCN-(aq) | Copper |
| Fe(OH)2 | Iron(II) hydroxide | 8 × 10-16 | Fe(OH)2(s) ⇌ Fe2+(aq) + 2 OH-(aq) | Iron |
| Fe(OH)3 | Iron(III) hydroxide | 4 × 10-38 | Fe(OH)3(s) ⇌ Fe3+(aq) + 3 OH-(aq) | Iron |
| FeCO3 | Iron(II) carbonate | 2.1 × 10-11 | FeCO3(s) ⇌ Fe2+(aq) + CO32-(aq) | Iron |
| FeS | Iron(II) sulfide | 3.7 × 10-19 | FeS(s) ⇌ Fe2+(aq) + S2-(aq) | Iron |
| Pb(OH)2 | Lead(II) hydroxide | 1.2 × 10-15 | Pb(OH)2(s) ⇌ Pb2+(aq) + 2 OH-(aq) | Lead |
| Pb3(PO4)2 | Lead(II) phosphate | 1 × 10-54 | Pb3(PO4)2(s) ⇌ 3 Pb2+(aq) + 2 PO43-(aq) | Lead |
| PbBr2 | Lead(II) bromide | 4.6 × 10-6 | PbBr2(s) ⇌ Pb2+(aq) + 2 Br-(aq) | Lead |
| PbCl2 | Lead(II) chloride | 1.6 × 10-5 | PbCl2(s) ⇌ Pb2+(aq) + 2 Cl-(aq) | Lead |
| PbCO3 | Lead(II) carbonate | 1.5 × 10-15 | PbCO3(s) ⇌ Pb2+(aq) + CO32-(aq) | Lead |
| PbCrO4 | Lead(II) chromate | 2 × 10-16 | PbCrO4(s) ⇌ Pb2+(aq) + CrO42-(aq) | Lead |
| PbF2 | Lead(II) fluoride | 4 × 10-8 | PbF2(s) ⇌ Pb2+(aq) + 2 F-(aq) | Lead |
| PbI2 | Lead(II) iodide | 1.4 × 10-8 | PbI2(s) ⇌ Pb2+(aq) + 2 I-(aq) | Lead |
| PbS | Lead(II) sulfide | 7 × 10-29 | PbS(s) ⇌ Pb2+(aq) + S2-(aq) | Lead |
| PbSO4 | Lead(II) sulfate | 1.3 × 10-8 | PbSO4(s) ⇌ Pb2+(aq) + SO42-(aq) | Lead |
| Mg(OH)2 | Magnesium hydroxide | 8.9 × 10-12 | Mg(OH)2(s) ⇌ Mg2+(aq) + 2 OH-(aq) | Magnesium |
| MgC2O4 | Magnesium oxalate | 7 × 10-7 | MgC2O4(s) ⇌ Mg2+(aq) + C2O42-(aq) | Magnesium |
| MgCO3·3H2O | Magnesium carbonate trihydrate | ≈ 1 × 10-5 | MgCO3·3H2O(s) ⇌ Mg2+(aq) + CO32-(aq) + 3 H2O(l) | Magnesium |
| MgF2 | Magnesium fluoride | 6.4 × 10-9 | MgF2(s) ⇌ Mg2+(aq) + 2 F-(aq) | Magnesium |
| MgNH4PO4 | Magnesium ammonium phosphate | 3 × 10-13 | MgNH4PO4(s) ⇌ Mg2+(aq) + NH4+(aq) + PO43-(aq) | Magnesium |
| Mn(OH)2 | Manganese(II) hydroxide | 2 × 10-13 | Mn(OH)2(s) ⇌ Mn2+(aq) + 2 OH-(aq) | Manganese |
| MnCO3 | Manganese(II) carbonate | 1.8 × 10-11 | MnCO3(s) ⇌ Mn2+(aq) + CO32-(aq) | Manganese |
| MnS | Manganese(II) sulfide | 2.3 × 10-13 | MnS(s) ⇌ Mn2+(aq) + S2-(aq) | Manganese |
| Hg2Br2 | Mercury(I) bromide | 1.3 × 10-22 | Hg2Br2(s) ⇌ Hg22+(aq) + 2 Br-(aq) | Mercury |
| Hg2Cl2 | Mercury(I) chloride | 1.1 × 10-18 | Hg2Cl2(s) ⇌ Hg22+(aq) + 2 Cl-(aq) | Mercury |
| Hg2CO3 | Mercury(I) carbonate | 9 × 10-15 | Hg2CO3(s) ⇌ Hg22+(aq) + CO32-(aq) | Mercury |
| Hg2CrO4 | Mercury(I) chromate | 2 × 10-9 | Hg2CrO4(s) ⇌ Hg22+(aq) + CrO42-(aq) | Mercury |
| Hg2I2 | Mercury(I) iodide | 4.5 × 10-29 | Hg2I2(s) ⇌ Hg22+(aq) + 2 I-(aq) | Mercury |
| Hg2O·H2O | Mercury(I) oxide monohydrate | 3.6 × 10-26 | Hg2O·H2O(s) ⇌ Hg22+(aq) + 2 OH-(aq) | Mercury |
| Hg2S | Mercury(I) sulfide | 1.0 × 10-47 | Hg2S(s) ⇌ Hg22+(aq) + S2-(aq) | Mercury |
| Hg2SO4 | Mercury(I) sulfate | 7.4 × 10-7 | Hg2SO4(s) ⇌ Hg22+(aq) + SO42-(aq) | Mercury |
| HgS | Mercury(II) sulfide | 1.6 × 10-54 | HgS(s) ⇌ Hg2+(aq) + S2-(aq) | Mercury |
| Ni(OH)2 | Nickel(II) hydroxide | 2 × 10-15 | Ni(OH)2(s) ⇌ Ni2+(aq) + 2 OH-(aq) | Nickel |
| NiCO3 | Nickel(II) carbonate | 1.4 × 10-7 | NiCO3(s) ⇌ Ni2+(aq) + CO32-(aq) | Nickel |
| NiS(α) | Nickel(II) sulfide (alpha form) | 4 × 10-20 | NiS(α)(s) ⇌ Ni2+(aq) + S2-(aq) | Nickel |
| NiS(β) | Nickel(II) sulfide (beta form) | 1.3 × 10-25 | NiS(β)(s) ⇌ Ni2+(aq) + S2-(aq) | Nickel |
| K2PtCl6 | Potassium hexachloroplatinate(IV) | 7.48 × 10-6 | K2PtCl6(s) ⇌ 2 K+(aq) + PtCl62-(aq) | Potassium |
| KClO4 | Potassium perchlorate | 1.05 × 10-2 | KClO4(s) ⇌ K+(aq) + ClO4-(aq) | Potassium |
| KHC4H4O6 | Potassium hydrogen tartrate | 3 × 10-4 | KHC4H4O6(s) ⇌ K+(aq) + HC4H4O6-(aq) | Potassium |
| Ag2CO3 | Silver carbonate | 8.1 × 10-12 | Ag2CO3(s) ⇌ 2 Ag+(aq) + CO32-(aq) | Silver |
| Ag2CrO4 | Silver chromate | 9.0 × 10-12 | Ag2CrO4(s) ⇌ 2 Ag+(aq) + CrO42-(aq) | Silver |
| Ag2S | Silver sulfide | 1.6 × 10-49 | Ag2S(s) ⇌ 2 Ag+(aq) + S2-(aq) | Silver |
| Ag2SO4 | Silver sulfate | 1.2 × 10-5 | Ag2SO4(s) ⇌ 2 Ag+(aq) + SO42-(aq) | Silver |
| Ag3PO4 | Silver phosphate | 1.77 × 10-18 | Ag3PO4(s) ⇌ 3 Ag+(aq) + PO43-(aq) | Silver |
| Ag4Fe(CN)6 | Silver ferrocyanide | 1.55 × 10-41 | Ag4Fe(CN)6(s) ⇌ 4 Ag+(aq) + [Fe(CN)6]4-(aq) | Silver |
| AgBr | Silver bromide | 5.0 × 10-13 | AgBr(s) ⇌ Ag+(aq) + Br-(aq) | Silver |
| AgCl | Silver chloride | 1.8 × 10-10 | AgCl(s) ⇌ Ag+(aq) + Cl-(aq) | Silver |
| AgCN | Silver cyanide | 1.2 × 10-16 | AgCN(s) ⇌ Ag+(aq) + CN-(aq) | Silver |
| AgI | Silver iodide | 8.3 × 10-17 | AgI(s) ⇌ Ag+(aq) + I-(aq) | Silver |
| AgSCN | Silver thiocyanate | 1.0 × 10-12 | AgSCN(s) ⇌ Ag+(aq) + SCN-(aq) | Silver |
| Sr(OH)2·8H2O | Strontium hydroxide octahydrate | 3.2 × 10-4 | Sr(OH)2·8H2O(s) ⇌ Sr2+(aq) + 2 OH-(aq) + 8 H2O(l) | Strontium |
| SrC2O4·H2O | Strontium oxalate monohydrate | 4 × 10-7 | SrC2O4·H2O(s) ⇌ Sr2+(aq) + C2O42-(aq) + H2O(l) | Strontium |
| SrCO3 | Strontium carbonate | 7 × 10-10 | SrCO3(s) ⇌ Sr2+(aq) + CO32-(aq) | Strontium |
| SrCrO4 | Strontium chromate | 3.6 × 10-5 | SrCrO4(s) ⇌ Sr2+(aq) + CrO42-(aq) | Strontium |
| SrF2 | Strontium fluoride | 2.5 × 10-9 | SrF2(s) ⇌ Sr2+(aq) + 2 F-(aq) | Strontium |
| SrSO4 | Strontium sulfate | 3.2 × 10-7 | SrSO4(s) ⇌ Sr2+(aq) + SO42-(aq) | Strontium |
| Tl(OH)3 | Thallium(III) hydroxide | 6.3 × 10-46 | Tl(OH)3(s) ⇌ Tl3+(aq) + 3 OH-(aq) | Thallium |
| Tl2S | Thallium(I) sulfide | 6 × 10-22 | Tl2S(s) ⇌ 2 Tl+(aq) + S2-(aq) | Thallium |
| TlCl | Thallium(I) chloride | 1.7 × 10-4 | TlCl(s) ⇌ Tl+(aq) + Cl-(aq) | Thallium |
| TlSCN | Thallium(I) thiocyanate | 1.6 × 10-4 | TlSCN(s) ⇌ Tl+(aq) + SCN-(aq) | Thallium |
| Sn(OH)2 | Tin(II) hydroxide | 3 × 10-27 | Sn(OH)2(s) ⇌ Sn2+(aq) + 2 OH-(aq) | Tin |
| Sn(OH)4 | Tin(IV) hydroxide | 1.0 × 10-57 | Sn(OH)4(s) ⇌ Sn4+(aq) + 4 OH-(aq) | Tin |
| SnS | Tin(II) sulfide | 1 × 10-26 | SnS(s) ⇌ Sn2+(aq) + S2-(aq) | Tin |
| Zn(OH)2 | Zinc hydroxide | 1.2 × 10-17 | Zn(OH)2(s) ⇌ Zn2+(aq) + 2 OH-(aq) | Zinc |
| ZnCO3 | Zinc carbonate | 2 × 10-10 | ZnCO3(s) ⇌ Zn2+(aq) + CO32-(aq) | Zinc |
Important Notes
- All values at 25 °C (298.15 K). Solubility products span an enormous range — compare orders of magnitude, not digits.
- A smaller Ksp does NOT always mean a lower molar solubility: the dissolution stoichiometry (1:1 vs 1:2 vs 2:3 salts) enters the calculation, so always solve through the equilibrium expression.
- Fifteen entries carry course-curated values used consistently across ChemWhiz problems; the remainder follow the attributed source.
- Ksp applies to saturated solutions of sparingly soluble compounds; freely soluble salts (most nitrates, alkali salts) are not tabulated.
Source: OpenStax Chemistry 2e, Appendix J — Solubility Products (85 of 100 entries; 15 course-curated values take precedence where they differ) (CC BY 4.0)