# Office of Academic AffairsIndian Institute of Science Education and Research Bhopal

Chemistry

CHM 607: X-ray diffraction: Principles and Applications (4)

Learning Objectives:

The understanding of the three dimensional arrangement of atoms in crystalline solids and their relationship to chemical and biological function.

Course Contents:

Prerequisites: CHM 301; may be removed for other students subject to Instructor's discretion

Symmetry in the Solid State: Unit Cell, Crystal Systems, Crystal lattices (2D), Bravais Lattices (3D), Miller planes (crystallographic directions and multiplicities), d-spacing formula (resolution), Point Symmetry and Point Groups, Space groups (equivalent points, Wyckoff positions, site occupancy factor).

Elements of X-ray diffraction: Thomson and Compton Scattering, Interference of Scattered Waves, Scattering by an Atom and Crystal, Bragg’s Law, Reciprocal Lattice, Reflecting and Limiting sphere of reflection.

Preliminary concepts on Crystals and X-rays

Intensity and Geometric Data Collection and Reduction statistics, Factors that affect intensities (Lorentz and Polarization corrections), Interpretation of Intensity data, Wilson plot and absolute scale factor.

Theory of Structure Factors and Fourier Synthesis: Calculation of Structure Factor amplitudes (general formula and applications), Friedel’s Law, Systematically absent reflections, Anomalous Dispersion

Structure Solution and refinement: Patterson symmetry, Direct Methods, Least Squares Methods, Electron density maps, R-factors, refinement by DF synthesis.

Crystal structure determination: Asymmetric Unit, crystal density, unit cell contents, and chemical formula. Thermal Motion, the physical interpretation of molecular (Bond lengths, angles and torsions) and crystal structure (Packing Diagram), Rietveld method in Powder diffraction.

Suggested Readings :

• A Basic Course in Crystallography: J. A. K. Tareen & T. R. N. Kutty.
• Fundamentals of Crystallography: C. Giacavazzo.
• Basics of Crystallography and Diffraction: C. Hammond.
• X-ray Structure determination: A practical guide: G. H. Stout and L. H. Jensen.