I.  Symbols and Charges for Monoatomic Ions
A.  Fixed Charge
Symbol Name Symbol Name
H+ hydrogen ion H- hydride ion
Li+ lithium ion F- fluoride ion
Na+ sodium ion Cl- chloride ion
K+ potassium ion Br- bromide ion
Ag+ silver ion I- iodide ion
Mg2+ magnesium ion O2- oxide ion
Ca2+ calcium ion S2- sulfide ion
Ba2+ barium ion N3- nitride ion
Zn2+ zinc ion P3- phosphide ion
Al3+ aluminum ion
Bi3+ bismuth ion
B.  Variable Charge
Symbol Systematic Name Common Name Symbol Systematic Name Common Name
Cu+ copper(I) ion cuprous ion Hg22+ mercury(I) ion mercurous ion
Cu2+ copper(II) ion cupric ion Hg2+ mercury(II) ion mercuric ion
Fe2+ iron(II) ion ferrous ion Pb2+ lead(II) ion plumbous ion
Fe3+ iron(III) ion ferric ion Pb4+ lead(IV) ion plumbic ion
Sn2+ tin(II) ion stannous ion Co2+ cobalt(II) ion cobaltous ion
Sn4+ tin(IV) ion stannic ion Co3+ cobalt(III) ion cobaltic ion
Cr2+ chromium(II) ion chromous ion Ni2+ nickel(II) ion nickelous ion
Cr3+ chromium(III) ion chromic ion Ni4+ nickel(IV) ion nickelic ion
Mn2+ manganese(II) ion manganous ion Ti3+ titanium(III) ion titanous ion
Mn3+ manganese(III) ion manganic ion Ti4+ titanium(IV) ion titanic ion
II.  Symbols and Charges for Polyatomic Ions
Formula Name Formula Name
NO3- nitrate ion ClO4- perchlorate ion
NO2- nitrite ion ClO3- chlorate ion
CrO42- chromate ion ClO2- chlorite ion
Cr2O72- dichromate ion ClO- hypochlorite
CN- cyanide ion MnO4- permanganate ion
OH- hydroxide ion O22- peroxide ion
CO32- carbonate ion HCO3- hydrogen carbonate ion (bicarbonate ion)
SO42- sulfate ion HSO4- hydrogen sulfate ion (bisulfate ion)
SO32- sulfite ion HSO3- hydrogen sulfite ion (bisulfite ion)
C2O42- oxalate ion HC2O4- hydrogen oxalate ion (binoxalate ion)
PO43- phosphate ion HPO42- hydrogen phosphate ion
PO33- phosphite ion H2PO4- dihydrogen phosphate ion
HS- hydrogen sulfide ion (bisulfide ion)
C2H3O2-   acetate ion (an alternate way to write acetate is CH3COO-)
There is only one polyatomic cation, NH4+ = ammonium ion