Chemical Crystallography

The instructor has obtained his Ph. D. in 2005 from Indian Institute of Science, Bangalore working in the area of small molecule X-ray crystallography. Following that he has worked in the University of Liverpool as a post-doctoral fellow from October, 2004 to September, 2007. Then he moved to BITS, Pilani as Assistant Professor in Chemistry. From there, he moved to IISER Mohali in December, 2009 as Assistant Professor in chemistry. He has more than 70 publications in various international journals, guided two PhD students and a few masters students at IISER Mohali. He offers the same course at IISER Mohali in the August Semester.

COURSE LAYOUT:

Week 1  :  Introduction, 1D symmetry, Concept of 2D symmetry and lattices, notations of symmetry elements, space groups in 2D, 3D lattices, 32 point groups and their notations, crystal systems and Bravais lattices.
Week 2  :   Stereographic projections, Laue symmetry; glide planes, screw axes and their notations, space groups, equivalent points, space group symmetry diagrams etc.
Week 3  : Miller Indices, crystallographic planes and directions, close pack structures, linear density, planar density, Miller-Bravais indices for hexagonal systems, various ceramic structures (NaCl, ZnS, CaF2, CsCl etc.), octahedral and tetrahedral sites etc.
Week 4  :  What are X-rays, generation and classification of X-ray, X-ray sources, diffraction of X-rays, Bragg’s law.The reciprocal lattice, reciprocal relationship, Bragg’s law in reciprocal space, Ewald’s sphere and sphere of reflection
Week 5  :  Methods of crystal growth, identification of phases and morphologies, in-situ cryo crystallization, crystal growth under external stimuli etc.
Week 6  :  Data collection strategies, Laue Method, Oscillation, rotation and precession methods. L-P corrections, structure factor, scaling, interpretation of intensity data, temperature factor, symmetry from intensity statistics
Week 7  : Structure factor and Fourier synthesis, Friedel’s law; exponential, vector and general forms of structure factor, determination of systematic absences for various symmetry or lattice centering, FFT, Anomalous scattering and absolute configuration.
Week 8  : Phase problem, Direct Methods, structure invariants and semi invariants, probability methods, Phase determination in practice, Patterson Methods, Patterson Symmetry, completion of structure solution, F synthesis.
Week 9  : Refinement by Fourier synthesis, refinement by F synthesis, Refinement by least squares method, weighting functions, Goodness-of-Fit (GOF) parameter, treatment of non-hydrogen atoms, and treatment of hydrogen atoms, treatment of disordered structures.
Week 10  : Crystal selection, indexing of crystals, data collection, data reduction, space group determination, structure solution and refinement using SHELXS97 and SHELXL97, introduction to crystallographic packages (APEX II suite, OLEX2, WinGx, PLATON) and IUCr validation of the data
Week 11  : Methodology, geometrical basis of powder X-ray diffraction, applications of PXRD: determination of accurate lattice parameters, identification of new/unknown phases, applications in pharmaceutical industry.
Week 12  : Applications of powder X-ray diffraction: Structure determination from PXRD and Reitveld method for structure refinement, indexing of PXRD, handling of PXRD using DASH.

SUGGESTED READING MATERIALS:

1.X-ray structure determination: A Practical Guide (2nd Ed.) by George H. Stout and Lyle H Jensen, Wiley-Interscience, New York, 1989.
2.Fundamentals of Crystallography (2nd Ed.) by C. Giacovazzo, Oxford University Press, USA, 2002
3.X-ray analysis and The Structure of Organic Molecules (2nd Ed.) Wiley-VCH, New York, 1996
4.Chemical Applications of Group Theory (3rd Ed.) by F. A. Cotton, Wiley-India Edition, India, 2009.