Solubility Rules

Ammonium Ions NH₄⁺

Always Soluble

Nitrate Ions (NO₃^-)

Always Soluble 

Bicarbonate (HCO₃^-)

Always Soluble 

Chlorates (ClO₃^-)

Always Soluble 

Perchlorates (ClO₄^-)

Always Soluble 

Acetates (CH₃COO^-)

Always Soluble 

Li⁺

Always Soluble (Alkali Metal)

Na⁺

Always Soluble (Alkali Metal)

K⁺

Always Soluble (Alkali Metal)

Cs⁺

Always Soluble (Alkali Metal)

Rb⁺

Always Soluble (Alkali Metal)

Alkali Metals

Li, Na, K, Cs, Rb

F^-

Usually Soluble* - Pb2+, Hg2+, Ag+, Ba2+, Ca2+, Sr2+, Mg2+

Cl^-

Usually Soluble* - Pb2+, Hg2+, Ag+

Br^-

Usually Soluble* - Pb2+, Hg2+, Ag+

I^-

Usually Soluble* - Pb2+, Hg2+, Ag+

SO₄^2-

Usually Soluble* - Pb2+, Hg2+, Ag+, Ba2+, Ca2+, Sr2+

PO₄^3-

Insoluble except when paired with always soluble

CrO₄^2-

Insoluble except when paired with always soluble

Cr₂O₇^2-

Insoluble except when paired with always soluble

CO₃^2-

Insoluble except when paired with always soluble

S^2-

Insoluble* - except when paired with always soluble and Ba2+, Ca2+, Sr2+,

Metal Oxides (O^2-)

Insoluble, except when paired with always soluble

Metal Hydroxides (OH^- )

Insoluble* - except when paired with always soluble, and Ca, Ba, Sr