Ion-Specific Solubility Rules

Group I metals

Always soluble

NH4+

Always soluble

NO3-

Always soluble

ClO4-

Always soluble

C2H3O2-

Always soluble

Cl-

Soluble - exceptions: Ag+, Pb2+, Hg2^2+

Br-

Soluble - exceptions: Ag+, Pb2+, Hg2^2+

I-

Soluble - exceptions: Ag+, Pb2+, Hg2^2+

F-

Soluble - exceptions: Group 2 metals, Pb2+

SO4^2-

Soluble - exceptions: Ca2+, Sr2+, Ba2+, Pb2+, Hg2^2+

CO3^2-

Insoluble - exceptions: Group I metals, NH4+

CrO4^2-

Insoluble - exceptions: Group I metals, NH4+

PO4^3-

Insoluble - exceptions: Group I metals, NH4+

S^2-

Insoluble - exceptions: Group I metals, NH4+

OH-

Insoluble - exceptions: Group I metals, NH4+, Ca2+, Sr2+, Ba2+

Ag+

Forms insoluble salts with Cl-, Br-, I-

Pb2+

Forms insoluble salts with Cl-, Br-, I-, F-, SO4^2-

Hg2^2+

Forms insoluble salts with Cl-, Br-, I-, SO4^2-

Ca2+

Insoluble with SO4^2-, OH- (exception for OH-)

Sr2+

Insoluble with SO4^2-, OH- (exception for OH-)

Ba2+

Insoluble with SO4^2-, OH- (exception for OH-)