Some students find it really difficult to visualise the structure of complexes involving polydentate ligands. It might help them to think of a bidentate ligand being like a pair of headphones with a lone pair on each earpiece. The ligand earphones fit neatly around the metal atom as ordinary earphones fit around the head.

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As always with 3D structures, molecular models are very useful. Molecular models can be used to show the geometry of complexes with polydentate ligands. In some molecular model systems, flexible rubber tubes or cotton thread can be used to show how ligands bond to the metal ion in more than one place.

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Molecular modelling images and animations can be found on the internet that will reinforce the first-hand experience of students making their own models.