Preface

In the quantitative determination of new structures, micro-/nano-crystalline materials pose significant challenges in the field of materials, chemical and bio-chemical crystallography. The different properties of materials are structuredependent. Traditionally, X-ray crystallography has been used for the analysis of these materials. Electron crystallography offers an alternative approach in the study of very small crystals that are a million times smaller than those needed for X-ray diffraction. Under certain conditions, electron crystallography has some advantages over X-ray crystallography: it is possible to record single crystal information from individual micro-/nano crystals and sometimes it helps in the resolution of overlapped reflections in X-ray powder data. This is possible due to the greater scattering cross section of matter for electrons than X-rays. The defects in crystals can be studied using high resolution electron microscopy images. In recent years, electron diffraction has been widely applied for determining the structure of unknown crystals. With the introduction of advanced methodologies, important methods for crystal structural analysis in the field of electron crystallography have been discovered. There are two methods that are developed for collection of complete three-dimensional electron diffraction data: the rotation electron diffraction (RED) and automated electron diffraction tomography (ADT). Large numbers of crystal structures have been solved using the RED method. These include the most complex zeolites ever solved, open-framework compounds and quasicrystal approximants, such as the pseudo-decagonal approximants.

Chapter 1 is related to the introduction about the electron crystallography. In Chapter 2, electron diffraction, high resolution transmission and scanning transmission electron microscope imaging in materials research, especially in the study of nano-science, are presented. In Chapter 3, a comprehensive review and comparison of different methods used for generating the empires are presented. The focus is given to the 'cut and project method', which can be generalized to calculate empires for any quasicrystals. In Chapter 4, the structure analysis of complex pseudo-decagonal (PD) quasicrystal approximants PD2 and PD1 using the RED method have been discussed. PD2 and PD1 are built of characteristic 2 nm wheel clusters with 5-fold rotational symmetry. In Chapter 5, the crystallographic structure evolution of stainless steels during rolling, piercing and plasma nitriding is described and the mechanism of microstructure evolution during metal forming and materials processing is presented. The EBSD (Electron Back Scattering Diffraction) technique is employed for the crystallographic analysis. In Chapter 6, the experimental and theoretical charge-density analysis has been performed to understand the topological and electrostatic properties of the 1-10 phenanthroline hydrate molecule. In Chapter 7, a study on the interaction of dislocation-dopant ions during plastic deformation by strain-rate cycling tests has been presented and discussed.

We wish to express our sincere appreciation to IntechOpen for giving us the opportunity to publish a book on the topic of electron crystallography. We would like to thank all the authors for their significant contributions and for providing high-quality research to share worldwide. We hope that this book will support current researchers and prove to be very useful to the scientific community. We also want to express our sincere gratitude to Ms. Dolores Kuzelj for her help during the entire publication process.
