Oxalate ion

[Claire_Kim_2F]

I was wondering why oxalate is only a bidente because there is four oxygens in it that can be bound.

[Gillian Gabrielsen2F]

Because of it's geometry, only two oxygens can bound at a time. Each carbon has a trigonal planar geometry, which means the bond angles are ~ 120 degrees, so all 4 oxygens are unable to bond with the same central metal atom. Here's a picture, where you can see that the non bound oxygens are on the other side of the molecule, away form the metal, so they're unable to form bonds with it. Hope this helps

[Madeline Louie 1I]

Gillian explained it really well. You have to consider the location of the atoms, structure of the molecule, double bonds, and possibly the bonding affinity. For other structures, double bonds may limit the rotation and ability to have the atoms located in the right place. For oxalate, the oxygens with a single bond have a negative formal charge, so they want to donate their electrons to the central metal atom in order to become more stable more than the double bonded oxygens with a formal charge of zero.

[Astha Sahoo 3I]

The structure of the molecule is in such a way that wherever you place the metal, only two oxygens can be bound to it. Gillian explained it really well, and I think the picture she provided is really helpful in explaining why only two oxygens can bind.

[Janna Shakiba]

It's bidente because it needs to receive two electrons total to get to its ground state.

[RitaThomas_3G]

A bidente is defined when it is bound to two atoms. If we look at the structure of oxalate, we see that when looking at only one Carbon atom, it is only bound to two Oxygen atoms. Therefore, it is characterized as a bidente.