Coordination Compounds

PAC-II COMPLEXOMETRIC TITRATION

Course Contents:

C OMPLEXOMETRIC
TITRATION
T ITRATION

Complexation, Chelation.
Werner’s co-ordination number, Titrants
Stability of complexes, titration curves.
Types of complexometric titrations.
Methods of detecting end point,
Standardization.
 Application of complexometric titrations.






COMPLEXOMETRIC TITRATIONS

COMPLEXOMETRIC TITRATIONS

What is Complexometric Titration (CT)????
What
What is a complex metal ion?
A complex is a molecule or ion formed by the reaction of two or more ions or molecules capable of independent existence. What is COMPLEXATION?????
Chemical reaction that takes place between the metal ion and a molecular or ionic entity (known as ligand).

 Also known as Chilometric titration, Chilometry, Chilatometric,
EDTA titrations.
 It is a form of volumetric analysis in which the formation of a colored complex is used to indicate the end point of a titration.
 The technique involves titrating metal ions with a complexing agent or chelating agent (Ligand) and is commonly referred to as complexometric titration.
 This method represents the analytical application of a complexation reaction.
 The endpoint is usually measured with an indicator ligand that forms a colored complex with the free metal ion.
CT are useful for determination of mixture of different metal ions in solution.

COMPLEXOMETRIC TITRATIONS

4

COMPLEXOMETRIC TITRATIONS

1

PAC-II COMPLEXOMETRIC TITRATION

LIGANDS:

Metal ion ( analyte ; cation) Metal ion indicators Chilon
Complexing
agent

pM indicators

( Chelating agent
L igand/Sequestering agent)

Chelate
Complex ion
Metal co -ordination compound
/Metal complex/Chelate compound  Ligands or complexing or chelating agents are electron donating entity, which has the ability to bind to the metal ion and produce a complex ion.  The molecules or ions which displace the solvent molecules are