## Distinguishing between using () and [] [ENDORSED]

Delacey Rodriguez 1D
Posts: 7
Joined: Fri Jun 17, 2016 11:28 am

### Distinguishing between using () and []

Can someone explain when we would use the brackets compared to using parentheses?
Thanks!

Chem_Mod
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### Re: Distinguishing between using () and []  [ENDORSED]

Stuff in [] (brackets) usually denote a molecule that is charged and part of a salt. We commonly see this used in transition metal salts, like [Co(NH3)6]Cl3. The stuff inside the brackets has a +3 charge, while the 3 Chlorines outside the bracket contribute a negative charge, each.

Parenthesis are often used to notify the reader that whatever is inside the parenthesis is grouped together. In the example I provided above, we know that (NH3)6 is 6 ammonia ligands. If the parenthesis weren't present we can see how this would be pretty ambiguous and complicated. Do we have 18 hydrogens? 6 nitrogens? maybe 6 nitrogens bonded all together? You get the idea...