[abhi001234]

I had a simple doubt about IUPAC system of nonenclature for coordination compounds.
We use prefixes like bis- , tris- , tetrakis-
for polydentate chilating ligands.
So why dont we use these prefixes for the bidentate ligand oxalato when we use these prefixes for all other bi,tri,tetradentate chelating ligands??

[Hunter2]

It is used for larger units,

http://en.wiktionary.org/wiki/tetrakis-