Ethane-1,2-diamine (en) is an example of a/an:

Step-by-step solution

Ethane-1,2-diamine (H₂ N-CH₂ -CH₂ -NH₂ ) contains two nitrogen atoms, each possessing a lone pair of electrons. It can coordinate to a central metal ion through both of these nitrogen atoms simultaneously, making it a bidentate (or didentate) ligand. It is not an ambidentate ligand because it does not have two different types of donor atoms to choose from, and it is not a monodentate ligand because it binds through two sites. Answer: bidentate ligand with two nitrogen donor atoms