Coming soon
Molecular Structure and Bonding
To learn molecular structure, types of bonding in main group elements and basics of conductors, semiconductors and superconductors.
Pre requisite : Introductory study of different types of bonding and their general properties mentioned in semester I.
Introduction, radius ratio rules- calculation of limiting radius ratio values for coordination number 3,4 ,6 and 8; close packing; classification of ionic structures, ionic compounds of the type AX (ZnS, NaCl, CsCl) and AX2 (CaF2-Fluorite), limitations of radius ratio rule; calculation of lattice energy, factors affecting lattice energy, the Born Haber cycle and its application; solvation energy and solubilities of ionic substances; stoichiometric and non stoichiometric defects.
The Lewis theory, octet rule, explanations for the failure of octet rule,exceptions to octet rule; valence bond theory (Heitler and London approach) and its limitations; resonance; directional character of covalent bond, various types of hybridization ( sp, sp2, sp3, sp3d,sp3d2, dsp2, sp3d3) and shapes of molecules; VSEPR theory, isoelectronic principle, examples using VSEPR theory, polarizability of ions, Fajan’s rule and consequences of polarization, dipole moment and percentage ionic character in covalent compounds (electronegativity difference and dipole moment method), bond energy and bond length.
Introduction, LCAO approach, combination of orbitals (s-s, s-p, p-p, non-bonding combination of orbitals), examples of molecular orbital treatment for homonuclear diatomic molecules – H2+, H2, He2, B2, C2, N2, Be2, O2, O2+1, O2-1, O2-2, F2, examples of molecular orbital treatment for heteronuclear diatomic molecules- NO, NO+, CO, CO+, CN molecule, comparison of VBT and MOT.
Multicentred bonding in electron deficient molecule; general properties of metals– conductivity, lustre, malleability, ductility, crystal structures; theories of bonding in metals – free electron theory, valence bond theory and band theory – conductors, insulators and semi-conductors; superconductors.
Van der Waal’s forces: ion-dipole forces, dipole-dipole interactions, induced dipole interactions, instantaneous dipole – induced dipole interactions, repulsive forces.
Hydrogen bond: types, theories and properties of H-bond, effects of H-bond on physical properties.
1. A New Concise Inorganic Chemistry; Fifth Edition; J.D. Lee; Blackwell Science, London, 1989.
2. Inorganic Chemistry; Third Edition; D.F. Shriver and P.W. Atkins; Oxford University Press, New York, 1999
