Explain with two examples each of the following: coordination entity, ligand, coordination number, coordination polyhedron, homoleptic and heteroleptic.

Explanation

Coordination entity or coordination compound: A coordination entity or coordination compound constitutes a central metal atom or ion bonded to a fixed number of ions or molecules.
For example, `[CoCl_2(NH_3)_3]` is a coordination entity in which the cobalt ion is surrounded by three ammonia molecules and three chloride ions. Other examples are `[Ni(CO)_4], [PtCl_2 (NH_3)_2], [Fe(CN)_6]^(4-), [CO(NH_3)_6]^(3+)`.