Single crystals are formed when the process of crystallization occurs at extremely slow rate. Even these crystals are not free of defects. The defects are basically irregularities in the arrangement of constituent particles.
Broadly speaking, the defects are of two types, namely, point defects and line defects.
Point defects
Point defects are the irregularities or deviations from ideal arrangement around a point or an atom in a crystalline substance, whereas the line defects are the irregularities or deviations from ideal arrangement in entire rows of lattice points. These irregularities are called crystal defects.
Types of Point Defects:
Point defects can be classified into three types:
- Stoichiometric defects
- Impurity defects
- Non-Stoichiometric defects