There are groups of covalently bound atoms that act like a single ion. An OH has a negative charge and will combine with one sodium ion like a chloride ion. A list of these polyatomic ions is shown below.
Polyatomic ions and their names:
| Formula |
Name |
| NH4+ |
Ammonium |
| OH- |
Hydroxide
|
| NO3- |
Nitrate |
| NO2- | Nitrite |
| CH3CO2- |
Acetate |
| CN- |
Cyanide |
| MnO4- |
Permanganate |
| CO32- |
Carbonate |
| HCO3-‑ |
Bicarbonate |
| SO32- |
Sulfite |
| HSO3- |
Bisulfite |
| SO42- |
Sulfate |
| PO43- |
Phosphate |
| HPO42- |
Hydrogen
phosphate |
| H2PO4- |
Dihydrogen
phosphate |
| SiO32- |
Silicate |
| CrO42- |
Chromate |