Common Polyatomic Ions
Name Formula Charge
acetate $\ce{C_2H_3O_2^-}$ -1
ammonium $\ce{NH_4^+}$ +1
arsenate $\ce{AsO_4^3-}$ -3
borate $\ce{BO_3^3-}$ -3
carbonate $\ce{CO_3^2-}$ -2
chlorate $\ce{ClO_3^-}$ -1
chromate $\ce{CrO_4^2-}$ -2
cyanide $\ce{CN^-}$ -1
dichromate $\ce{Cr_2O_7^2-}$ -2
hydroxide $\ce{OH^-}$ -1
nitrate $\ce{NO_3^-}$ -1
permanganate $\ce{MnO_4^-}$ -1
phosphate $\ce{PO_4^3-}$ -3
selenate $\ce{SeO_4^2-}$ -2
sulfate $\ce{SO_4^2-}$ -2