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Common Polyatomic Ions and Acids
A polyatomic ion or molecular ion is a group of atoms all connected with covalent bonds that collectively have a positive or negative charge. It will be useful to know the names, formulas, and charges of the following polyatomic ions.
Cations: positively charged ions
Anions: negatively charged ions
| CO32- | carbonate |
| HCO3- | hydrogen carbonate or bicarbonate |
| C2H3O2- | acetate |
| CH3COO- | acetate |
| CN- | cyanide |
| | |
| NO2- | nitrite |
| NO3- | nitrate |
| | |
| O22- | peroxide |
| O2- | superoxide |
| OH- | hydroxide |
| | |
| SiO44- | silicate |
| | |
| PO33- | phosphite |
| PO43- | phosphate |
| HPO42- | hydrogen phosphate |
| H2PO4- | dihydrogen phosphate |
| | |
| SO32- | sulfite |
| SO42- | sulfate |
| HSO3- | hydrogen sulfite or bisulfite |
| HSO4- | hydrogen sulfate or bisulfate |
| | |
| ClO- | hypochlorite (the active ingredient in bleach) |
| ClO2- | chlorite |
| ClO3- | chlorate |
| ClO4- | perchlorate |
| | |
| MnO4- | permanganate |
| CrO42- | chromate |
| Cr2O72- | dichromate |
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