Explain the violet colour of the complex `[Ti(H_(2)O)_(6)]^(3+)` on the basis of crystal field theory.

Explanation

Formation of a complex in solution is an equilibrium reaction it may be represented as `M+4LhArr M L_(4)`
The equilibrium constant of this reaction is the measure of stability of the complex Hence the equilibrium constant is also called as stability constant or instability constant may be defined as equilibrium constant for reverse reaction The formation of above complex may also be written in successive steps:
`M+L hArr ML K_(1)`
`ML+LhArr ML_(2) K_(2)`
`ML_(2) hArr ML_(3) K_(3)`
`ML_(3)+L hArr ML_(4) K_(4)`
Stability constant is written as
`beta_(4)=K_(1)K_(2)K_(3)K_(4)`
Greater the stablity constant stronger is the metal ligand bond The stability of complex will depend on
(a) nature of metal
(b) Oxidation state of metal
(c) Nature of ligand eg. chelating ligand form stabler complexes
(d) Greater the basic strength of the ligand more will be the stability