Appendix K | Solubility Rules for Common Ionic Compounds in Water

Solubility Rules for Common Ionic Compounds in Water

Soluble compounds contain

group 1 metal cations (Li⁺, Na⁺, K⁺, Rb⁺, and Cs⁺) and ammonium ion (NH₄⁺)

the halide ions (Cl⁻, Br⁻, and I⁻)

the acetate (C₂H₃O₂⁻), bicarbonate (HCO₃⁻), nitrate (NO₃⁻), and chlorate (ClO₃⁻) ions

the sulfate (SO₄²⁻) ion

Exceptions to these solubility rules include

halides of Ag⁺, Hg₂²⁺, and Pb²⁺

sulfates of Ag⁺, Ba²⁺, Ca²⁺, Hg₂²⁺, Pb²⁺, and Sr²⁺

Insoluble compounds contain

carbonate (CO₃^2-), chromate (CrO₄^2-), phosphate (PO₄^3-), and sulfide (S^2-) ions

hydroxide ion (OH^–)

Exceptions to these insolubility rules include

compounds of these ions with group 1 metal cations and ammonium ion

hydroxides of group 1 metal cations and Ba²⁺