Chelating Ligands

[Ethan Mai 1D]

The textbook mentions that many polydentates are chelates, which makes sense since they are able to bond with a cation at more than one site. Are there any common examples of polydentates which are not chelates, and where would the "extra" binding sites bind to?

[AngelinaYuleiGao 1B]

My guess is that in order for the polydentate ligand to not chelate, it doesn't bind with the central cation multiple times even though it is able to; it simply binds once, then binds to a different cation. That way, the ligand does not chelate, as it doesn't form a ring, but is still polydentate. If I'm wrong please correct me, but that makes the most sense in my head. Hope it helps!