Theoretical Background of Molecular and Crystal Chemistry. Molecular Structure, Crystal Structure, Crystal Lattice. Symmetry, Symmetry Operations, Point and Space Symmetry Groups, Symmetry Operation of Space Groups. Crystal Symmetry, Crystallographic Lattices, Crystal Lattice Structures and Its Characterization. The Nature of Selected Radiations, Sources and Detections, Interaction of Radiation with Crystalline Matter, Diffraction, X-ray Diffraction Methods (Powder Diffraction Method and Single Crystal Method). The Use of Diffraction Methods for Structure Determination (X-ray Structure Analysis, Electron Diffraction and Neutron Diffraction). The Base of X-ray Structure Analysis, Possibility of Data Obtaining and Its Evaluation, Obtaining 3D Structure Molecular Model. The Use of Diffraction Methods for High-molecular Matter Study (Polymer, Protein and Other Biological Macromolecules).