ABSTRACT
This chapter discusses the crystal chemistry, review specific metallic and ceramic crystal structures, and finish by considering the various crystal defects and accommodation of off-stoichiometry in ceramics. The crystal structure that results depends upon the type of atomic bonding, the size of the atoms, and the electrical charge of the ions. Crystal directions are identified by the square-bracketed coordinates of a ray that extends from the origin to a corner, edge, or face of the unit cell. Pure metals form crystal structures that are relatively close packed and consist of atoms all the same size and electrical charge distribution. The size of an ion is the most critical parameter in the science of crystal chemistry. Most of the ionic ceramic crystal structures consist of a three-dimensional stacking of the anions with the smaller cations fitting into interstitial positions. Electrical neutrality is required at the unit-cell level as well as throughout the crystal structure.
