A List of Common Polyatomic Ions With Charges and Oxidation Numbers

List of Common Polyatomic Ions with Charges and Oxidation Numbers
An ion is an atom or molecule that has acquired an electric charge due to loss or gain of electrons. Thus, a polyatomic ion is an ion that is composed of 2 or more atoms. ScienceStruck lists down some common polyatomic ions with their charges and oxidation numbers.
ScienceStruck Staff
Last Updated: Apr 28, 2018
Did You Know?
A negatively charged polyatomic ion that has one or more oxygen atoms bonded to another element is known as an oxyanion; for e.g. the sulphate, nitrate, and carbonate ions.
A polyatomic ion is composed of two or more atoms, and it carries a charge that is positive or negative.

When a polyatomic ion takes part in a chemical reaction, its oxidation number plays a significant role. The oxidation number is also known as Oxidation State. It is a number that is either positive, negative, or zero. The oxidation number of an ion indicates the number of electrons that an ion can gain, lose, or share when chemically reacting with another ion (monatomic or polyatomic), atom, compound, or molecule.

The oxidation number of a polyatomic ion is the sum of oxidation numbers of its constituent atoms. It is equal to the charge on the ion.
Common Polyatomic Ions
Polyatomic Ion Chemical Symbol Charge Oxidation Number
Ammonium NH4+ +1 +1
Phosphonium PH4+ +1 +1
Hydronium H3O+ +1 +1
Fluoronium H2F+ +1 +1
Tropylium C7H7+ +1 +1
Guanidine C(NH2)3+ +1 +1
Mercury Hg22+ +2 +2
Acetate C2H3O2- -1 -1
Bicarbonate HCO3- -1 -1
Bisulphate HSO4- -1 -1
Bisulfite HSO3- -1 -1
Bromate BrO3- -1 -1
Bromite BrO2- -1 -1
Chlorate ClO3- -1 -1
Chlorite ClO2- -1 -1
Cyanide CN- -1 -1
Hydroxide OH- -1 -1
Hypobromite BrO- -1 -1
Hypochlorite ClO- -1 -1
Hypoiodite IO- -1 -1
Iodate IO3- -1 -1
Iodite IO2- -1 -1
Nitrate NO2- -1 -1
Nitrite NO2- -1 -1
Perbromate HBrO3- -1 -1
Perchlorate ClO4- -1 -1
Permanganate MnO4- -1 -1
Dihydrogen phosphate H2PO4- -1 -1
Carbonate CO32- -2 -2
Chromate CrO42- -2 -2
Dichromate Cr2O72- -2 -2
Oxalate C2O42- -2 -2
Peroxide O22- -2 -2
Sulfate SO42- -2 -2
Sulfite SO32- -2 -2
Thiosulfite S2O32- -2 -2
Hydrogen phosphate HPO42- -2 -2
Ferricyanide Fe(CN)63- -3 -3
Phosphate PO43- -3 -3
Ferrocyanide Fe(CN)64- -4 -4