Stability, Bonding and Inorganic Reaction Mechanism

Paper Code: 
CHY 121
Contact Hours: 
Max. Marks: 

Course Objectives :

The course aims to make the students explain about the various methods of determination of stability constants, to enable the students to learn about kinetics and reaction mechanism of transition metal complexes, and to acquaint the students with the nature of metal-ligand bonding in coordination compounds on the basis of Molecular Orbital Theory.

Course Outcomes (COs):                                                                                                                                  


Learning outcomes (at course level)

Learning and teaching strategies

Assessment Strategies

Paper Code

Paper Title

CHY 121

Stability, Bonding and Inorganic Reaction Mechanism

The students will be able to-

CO1-determine the stability constants of complexes by various methods.

CO2-predict kinetics and mechanism of ligand substitution reactions in transition metal complexes

CO3-construct molecular orbital diagrams of complexes using the fundamental knowledge of quantum mechanics

Interactive lectures








Problem solving

Written test






Semester end examination



Unit I: 
Stability of Complex Ions in Solution

Thermodynamic and kinetic stability, stepwise and overall formation constants, factors affecting stability of complexes. Determination of the stability constants of complexes: pH-metric method, ion exchange method, spectrophotometric method and polarographic method, determination of composition of complexes: Job’s method (method of continuous variation), mole ratio method, slope-ratio method.


Unit II: 
Mechanism of Reactions of Transition Metal Complexes-I

Kinetics of substitution reactions in octahedral complexes, acid hydrolysis(SN1 mechanism), factors affecting acid hydrolysis and base hydrolysis, conjugate base mechanism(SN1cB mechanism), direct and indirect evidence in favor of conjugate mechanism. Anation reactions: Reactions without metal ligand bond cleavage, Berrys’s pseudo rotation mechanism.

Self-Study: Ligand Substitution Reactions: Patterns of reactivity, classification of mechanisms: Associative, dissociative and interchange mechanism of substitution, energy profile of reaction transition states. inert and labile complexes.


Unit III: 
Mechanism of Reactions of Transition Metal Complexes-II

Trans effect, theories of trans effect and its uses, mechanism of substitution in square planar complexes, factors affecting substitution reactions in square planar complexes, Swain Scott equation, cis-trans isomerization.

Redox Reactions: Classification, mechanism of one electron transfer reaction: outer sphere type reactions, cross reactions and Marcus-Hush theory (qualitative treatment), inner sphere type reactions, two electron transfer reaction (brief idea).


Unit IV: 
Molecular Orbital Theory-I (σ-bonding)

Ligand Field Theory: An introduction, molecular orbital diagrams of some simple polyatomic molecules like BeH2, H2O, NH3, Walsh diagrams: LCAO’s approximation, σ-only molecular orbital energy levels for octahedral, tetrahedral and square planar complexes.


Unit V: 
Molecular Orbital Theory-II (π-bonding)

Molecular orbital energy levels for octahedral, tetrahedral and square planar complexes containing π-bonds, effect of pi-bonding. Experimental evidences for π-bonding: crystallography and Infra-red spectroscopy.

Angular Overlap Model: Principles, σ- and π- bonding in octahedral complexes

  • Inorganic Chemistry; Fifth Edition; D.F. Shriver and P.W. Atkins; Oxford University Press, New York, 2004.
  • Inorganic Chemistry; Seventh International Edition; M. Weller, T. Overton, J. Rourke, F. Armstrong; Oxford University Press, New York, 2018.
  • Inorganic Chemistry (Principle and Structure and Reactivity); Fourth Edition; J. E Huheey, E. A. Keiter, R. L. Keiter; Pearson India, New Delhi, 2013
  • Advanced Inorganic Chemistry, Sixth Edition; F.A. Cotton, G. Wilkinson, C.A. Murillo, M. Bochmann; John Wiley and Sons, USA, New York, 2007.
  • Inorganic Chemistry; Fifth Edition; Gary L. Miessler and Donald A. Tarr; Pearson Education Inc. Singapore, 2013.
  • Fundamental Concepts of Inorganic Chemistry; Volume 4 &5, First Edition; A. K. Das and M. Das; CBS Publishers, New Delhi,2014.
Academic Year: