Q.What are cationic, anionic and neutral complexes? Give one example of each.

Coordination complexes are classified along two entirely independent axes. The first axis is by the TYPES of ligands present: a homoleptic complex has its metal ion bound to only ONE type of ligand throughout (e.g. [Co(NH3)6]3+, every ligand is NH3), while a heteroleptic complex has its metal ion surrounded by MORE THAN ONE type of ligand (e.g. [Co(NH3)4Cl2]+, which carries both NH3 and Cl- ligands together). The second axis is by the SIGN OF THE NET CHARGE carried specifically by the coordination sphere itself, considered alone inside its square brackets: a cationic complex has a positively charged coordination sphere (e.g. [Zn(NH3)4]2+, or the [Co(NH3)5Cl]2+ sphere inside [Co(NH3)5Cl]SO4); an anionic complex has a negatively charged coordination sphere (e.g. [Ni(CN)4]2-, or the [Fe(CN)6]3- sphere inside K3[Fe(CN)6]); and a neutral complex has neither -- its coordination sphere already carries zero net charge and therefore …