Which of these ligands is ambidentate — capable of binding through either of two different donor atoms?

1. Ambidentate ligands have two different donor atoms but bind through only one at a time. 2. SCN⁻ can bind via sulphur (thiocyanato-S) or via nitrogen (isothiocyanato-N). 3. NO₂⁻ is the other classic ambidentate example (nitro-N or nitrito-O). 4. NH₃, H₂O and Cl⁻ each have only one donor atom, so they are unidentate. _Source: syllabus Chemistry, Unit 5 "Coordination Compounds", §5.2(c)_