Werner's Co-ordination Theory
In 1893, Alfred Werner proposed a theory named as Werner's Co-ordination theory, in which he explained the concept of valence in metal complexes. According to him, there are two types of valences named as primary valence and secondary valence in metal complexes. 1) [Co(NH 3 ) 6 ]Cl 3 : According to the Werner's theory, in [Co(NH 3 ) 6 ]Cl 3 complex, the primary valence are satisfied by the three chloride ions (longer dotted line) while the six secondary valence are satisfied by six NH 3 molecules. These NH 3 molecules are very tightly bound to the cobalt metal and hence they don't dissociate in solution. The three Chloride ions are far away from the central cobalt metal and hence they are less firmly held by the metal atom. therefore all three Chloride ion dissociate in solution giving [Co(NH 3 ) 6 ] 3+ and 3Cl - ions , with total four ions. 2) [Co(NH 3 ) 5 Cl]Cl 2 : According to the Wer...