2: Defects and Non-stoichiometry

The ideal crystal structures discussed in Chapter 1 are not always found; often there are defects in the structure, which can occur in different ways. The defects can influence the material's properties significantly and hence are important to study and understand. This chapter outlines the general classes of defects in solids. After a brief look at intrinsic defects, extrinsic defects including the important problem of non-stoichiometry are discussed.