Rudiments of crystallography

Abstract

Crystallography deals basically with the question Where are the atoms in solids? The purpose of this chapter is to briefly introduce the basics of modern crystallography. The focus is on the description of periodic solids, which represent the major proportion of condensed matter. A coherent introduction to the formalism required to do this is given, and the basic concepts and technical terms crystallographyconcept and term are briefly explained. Paying attention to recent developments in materials research, we also discuss aperiodic, disordered, and amorphous matter. Consequently, besides the conventional three-dimensional (3-D) descriptions, the higher dimensional crystallographic approach is outlined, as well as the atomic pair distribution function used to describe local phenomena. The chapter then touches on the basics of diffraction methods, the most powerful tool kit used by experimentalists dealing with structure in solid-state research. Finally, the reader will be apprised of new developments in our understanding of order in condensed matter.