Unidentate ligands are those which bind to the metal ion through asingle donor atom. e.g., $Cl^{–}, H_2O$.Bidentate ligands are those which bind to the metal ion through two donoratoms. e.g., ethane-1,2-diamine$(H_2NCH_2CH_2NH_2)$, oxalate $(C_2O_4^{2–})$ ion.Ambidentate ligands are those which can bind to metal ion through twodifferent donor atoms. e.g., $NO_2^{–}$and $SCN^{–}$ion.