denticity

[Riya 14B-2]

Hey!

How do you determine the denticity of a ligand?

Thanks!

[Kelly McFarlane]

I think the best way is to look at the structure and determine how many bonds it can form.

[Riya Sawhney 1C]

Denticity refers to the number of bonds a single ligand can form with a central atom.For example, EDTA, shown below, is hexadentate, meaning it can form 6 bonds. Sigma bonds can rotate, and so parts of the molecule can rotate into the correct position.

[Sohan Talluri 1L]

To add on to the previous answer, for a ligand to be bidentate, it needs to include an "atom with a lone pair - spacer atom - spacer atom - atom with a lone pair" structure. For example, ethylene diamine (NH₂ - CH₂ - CH₂ - NH₂) is bidentate because each of its nitrogen atoms have a lone pair and are separated by two carbon atoms that are "spacers". Combining multiple of these "atom - spacer - spacer - atom" structures can result in molecules that have a higher denticity (such as EDTA).

Hopefully this helps and please correct me if there are any mistakes.