H2O and Carbonate

[305421980]

Why can't water and carbonate be polydentates?

[Eugene Chung 3F]

1. Water can't act as a polydentate because it is too small to form multiple bonds to a transition metal central atom. The lone pairs are both on the same O atom.
2. Carbonate can act as both mono and bidentate. Since it has two O atoms with - charge (lone pairs), it can interact in two places. It depends on the size of the cation.

[pauline young 1L]

adding onto this reply for water, even though there are two lone pairs, both are on the O. Since the lone pairs are on the same atom, it doesn't matter that there are two lone pairs, its still only monodentate

[RichBollini4G]

1. Water can't act as a polydentate because it is too small to form multiple bonds to a transition metal central atom. The lone pairs are both on the same O atom.
2. Carbonate can act as both mono and bidentate. Since it has two O atoms with - charge (lone pairs), it can interact in two places. It depends on the size of the cation.

very helpful, thank you!