Defects in Solid: Imperfections Solid crystalline state is characterized by a three – dimensional periodic arrangement of atoms, ions or molecules in space. Ideally, here should be a perfect order in such arrangement. However it is not so schottky defect.
Schottky defect any deviation from a completely orderly and stoichiometric ally perfect arrangement of atoms, ions or molecules in the crystal lattice is known as imperfection in crystals to achieve some specific objectives. In perfect crystals, all the constituent particles like atom, ions or molecules arranged in appetizer geometric order so that all the lattice points are occupied as required by the geometry and stoichiometry of the crystal. But in real crystals, there are always faults or imperfections in their lattices. These imperfections in crystalline solids are called defects in crystalline solids.
The defects in the solids can be minimized as follows:
- The crystalline solids are formed by cooling a substance in the liquid state which decreases the kinetic energy of atoms, ions or molecules.
- If the crystallization takes place faster, then the orderly arrangement of constituent particles cannot take place which produces defect in solids.
- The defects can be minimized by carrying out crystallization at the slowest rate, so that orderly arrangement of particles can take place.
- During slow crystallization, after the formation of a unit cell or one single crystal, deposition of other crystals from all directions takes place regularly forming a large crystal lattice.
- 1} Definition of Point Defects: The defects caused by a departure from the periodic arrangement of particles in the vicinity of an atom or group of atoms, are called point defects or point imperfections.
- 2} Definition of Lattice Defects: If the deviations from the periodic arrangement extend over microscopic regions, then the defects are called lattice imperfections or lattice defects. Lattice defects are of two types i.e., Line Defects and Plane defects.