| Term | Definition |
| alkali metal ion compounds | soluble |
| NH4^1+ (ammonium) | soluble |
| C2H3O2^1- (acetates) | soluble (exception: AgC2H3O2 is moderately soluble.) |
| NO3^1- (nitrates) | soluble |
| HCO3^1- (bicarbonates) | soluble |
| ClO3^1- (chlorates) | soluble |
| ClO4^1- (perchlorates) | soluble |
| halides | soluble (exceptions: of Ag^1+, Hg2^2+, Pb^2+) |
| SO4^2- (sulphates) | soluble (exceptions: of Ag^1+. Ca^2+. Sr^2+. Ba^2+, Hg2^2+, Hg^2+, Pb^2+) |
| CO3^2- (carbonates) | insoluble (exception: with alkali metals or NH4^1+ [ammonium]) |
| CrO4^2- (chromates) | insoluble (exception: with alkali metals or NH4^1+ [ammonium]) |
| F- (fluorides) | insoluble (exception: with alkali metals or NH4^1+ [ammonium]) |
| PO4^3- (phosphates)soluble (exception: with alkali metals or NH4^1+ [ammonium]) | insoluble (exception: with alkali metals or NH4^1+ [ammonium]) |
| SO3^2- (sulphites) | insoluble (exception: with alkali metals or NH4^1+ [ammonium]) |
| S^2- (sulphides) | insoluble (exception: with alkali metals, NH4^1+ [ammonium], Ca^2+, Sr^2+, Ba^2+) |
| O^2- (oxides) | insoluble (exception: alkali metals, NH4^1+ [ammonium], Ca^2+, Sr^2+ or Ba^2+ will react with water) |
| OH- (hydroxides) | insoluble (exceptions: with alkali metal ions or Ba^2+; Sr(OH)2 and Ca(OH)2 are moderately soluble) |