Polyatomic Ions

Polyatomic Ions

Singly Charged Cations

  • Ammonium: NH4+\text{NH}_4^+

Doubly Charged Cations

  • Mercury (I): Hg22+\text{Hg}_2^{2+}

Singly Charged Anions

  • Acetate: CH<em>3CO</em>2−\text{CH}<em>3\text{CO}</em>2^- or C<em>2H</em>3O2−\text{C}<em>2\text{H}</em>3\text{O}_2^-
  • Cyanide: CN−\text{CN}^-
  • Hypochlorite: ClO−\text{ClO}^-
  • Chlorite: ClO2−\text{ClO}_2^-
  • Chlorate: ClO3−\text{ClO}_3^-
  • Perchlorate: ClO4−\text{ClO}_4^-
  • Dihydrogen phosphate: H<em>2PO</em>4−\text{H}<em>2\text{PO}</em>4^-
  • Hydrogen carbonate (or bicarbonate): HCO3−\text{HCO}_3^-
  • Hydrogen sulfate (or bisulfate): HSO4−\text{HSO}_4^-
  • Hydroxide: OH−\text{OH}^-
  • Permanganate: MnO4−\text{MnO}_4^-
  • Nitrite: NO2−\text{NO}_2^-
  • Nitrate: NO3−\text{NO}_3^-
  • Thiocyanate: NCS−\text{NCS}^-

Doubly Charged Anions

  • Carbonate: CO32−\text{CO}_3^{2-}
  • Chromate: CrO42−\text{CrO}_4^{2-}
  • Dichromate: Cr<em>2O</em>72−\text{Cr}<em>2\text{O}</em>7^{2-}
  • Oxalate: C<em>2O</em>42−\text{C}<em>2\text{O}</em>4^{2-}
  • Peroxide: O22−\text{O}_2^{2-}
  • Hydrogen Phosphate: HPO42−\text{HPO}_4^{2-}
  • Sulfite: SO32−\text{SO}_3^{2-}
  • Sulfate: SO42−\text{SO}_4^{2-}
  • Thiosulfate: S<em>2O</em>32−\text{S}<em>2\text{O}</em>3^{2-}

Triply Charged Anion

  • Phosphate: PO43−\text{PO}_4^{3-}

Note: You MUST know all of these polyatomic ions.