For example, take a look at the following table. Notice anything about the Mercury(I) ion? Its ion symbol, Hg22+, shows that two mercury atoms are bonded together. This group has a 2+ charge, with each mercury cation having a 1+ charge. The mercurous ion is classified as a polyatomic ion.
Polyatomic ions are treated the same as monoatomic ions. The following list shows names and symbols for some important polyatomic ions.
![image0.png](https://www.dummies.com/wp-content/uploads/167944.image0.png)
![image1.png](https://www.dummies.com/wp-content/uploads/167945.image1.png)
![image2.png](https://www.dummies.com/wp-content/uploads/167946.image2.png)
![image3.png](https://www.dummies.com/wp-content/uploads/167947.image3.png)
![image4.png](https://www.dummies.com/wp-content/uploads/167948.image4.png)
![image5.png](https://www.dummies.com/wp-content/uploads/167949.image5.png)
![image6.png](https://www.dummies.com/wp-content/uploads/167950.image6.png)
![image7.png](https://www.dummies.com/wp-content/uploads/167951.image7.png)
![image8.png](https://www.dummies.com/wp-content/uploads/167952.image8.png)
![image9.png](https://www.dummies.com/wp-content/uploads/167953.image9.png)
![image10.png](https://www.dummies.com/wp-content/uploads/167954.image10.png)
![image11.png](https://www.dummies.com/wp-content/uploads/167955.image11.png)
![image12.png](https://www.dummies.com/wp-content/uploads/167956.image12.png)
![image13.png](https://www.dummies.com/wp-content/uploads/167957.image13.png)
![image14.png](https://www.dummies.com/wp-content/uploads/167958.image14.png)
![image15.png](https://www.dummies.com/wp-content/uploads/167959.image15.png)
![image16.png](https://www.dummies.com/wp-content/uploads/167960.image16.png)
![image17.png](https://www.dummies.com/wp-content/uploads/167961.image17.png)
![image18.png](https://www.dummies.com/wp-content/uploads/167962.image18.png)
![image19.png](https://www.dummies.com/wp-content/uploads/167963.image19.png)
![image20.png](https://www.dummies.com/wp-content/uploads/167964.image20.png)
![image21.png](https://www.dummies.com/wp-content/uploads/167965.image21.png)
![image22.png](https://www.dummies.com/wp-content/uploads/167966.image22.png)
![image23.png](https://www.dummies.com/wp-content/uploads/167967.image23.png)
![image24.png](https://www.dummies.com/wp-content/uploads/167968.image24.png)
![image25.png](https://www.dummies.com/wp-content/uploads/167969.image25.png)
![image26.png](https://www.dummies.com/wp-content/uploads/167970.image26.png)
![image27.png](https://www.dummies.com/wp-content/uploads/167971.image27.png)
![image28.png](https://www.dummies.com/wp-content/uploads/167972.image28.png)
As shown above, the symbol for the sulfate ion is:
![image29.png](https://www.dummies.com/wp-content/uploads/167973.image29.png)
This indicates that one sulfur atom and four oxygen atoms are bonded together and that the whole polyatomic ion has two extra electrons.