Coordination compounds are class of compounds by the presence of some central metal ion to a number of ligands .The electron pair used to form the bonds are donated by the ligands, which makes the ligands, Lewis bases and the metalion, a Lewis acid. Cobalt (III) form some of the most stableand easily prepared coordination compound. The cobalt (III)in pentaamminechlorocobalt(III) chloride has a coordination number of six: five NH3 and one Cl-ion, in an octahedral geometry around that cobalt (III) to give an ion with a 2+charge which is balanced by 2 Cl-counter ion