All compounds containing alkali metal cations and the ammonium ion are soluble.

All compounds containing NO₃^-, ClO₄^-, ClO₃^-, and C₂H₃O₂^- anions are soluble.

All chlorides, bromides, and iodides are soluble except those containing Ag⁺, Pb²⁺, or Hg₂²⁺.

All sulfates are soluble except those containing Hg₂²⁺, Pb²⁺, Sr²⁺, Ca²⁺, or Ba²⁺.

All hydroxides are insoluble except compounds of the alkali metals, Ca²⁺, Sr²⁺, and Ba²⁺.

All compounds containing PO₄^3-, S^2-, CO₃^2-, and SO₃^2- ions are insoluble except those that also contain alkali metals or NH₄⁺.