Usage of prefix

[Yiwen Chen-3G]

When do we use di, tri, tetra and when do we use bis, tris?

[Faith Fredlund 1H]

Use di, tri, tetra, etc. to indicate the number of each type of ligand in the complex ion; if there were two NH3 ligands in the complex, this portion would be called diammine. Use bis, tris, tetrakis, etc. when the ligand you are naming already contains a Greek prefix such as those listed above (di, tri, tetra), or when the ligand is polydentate (having more than one binding site at which it can connect to the central metal complex). For example, the coordination compound sodium bisoxalato(diaqua)ferrate(III) uses bis- to show that the ligand "oxalato" can bind at two sites, those being two of its oxygens.

[Sydni Stewart]

monodentate : di-,tri-,tetra-, penta-, hexa-

polydentate: bis-, tris-, tetrakis-