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List of Common Polyatomic Ions

Names, Formulas and Charges of Polyatomic Ions


This is a list of some of the most common polyatomic ions. It is worth committing the polyatomic ions to memory, including their molecular formulas and ionic charge.

Polyatomic Ion Charge = +1

Ammonium Ion
Todd Helmenstine

ammonium - NH4+

Polyatomic Ion Charge = -1

acetate - C2H3O2-
bicarbonate (or hydrogen carbonate) - HCO3-
bisulfate (or hydrogen sulfate) - HSO4-
chlorate - ClO3-
chlorite - ClO2-
cyanate - OCN-
cyanide - CN-
dihydrogen phosphate - H2PO4-
hydroxide - OH-
nitrate - NO3-
nitrite - NO2-
perchlorate - ClO4-
permanganate - MnO4-
thiocyanate - SCN-

Polyatomic Ion Charge = -2

carbonate - CO32-
chromate - CrO42-
dichromate - Cr2O72-
hydrogen phosphate - HPO42-
peroxide - O22-
sulfate - SO42-
sulfite - SO32-
thiosulfate - S2O32-

Polyatomic Ion Charge = -3

borate - BO33-
phosphate - PO43-
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