Imperfections in Solids
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Constituent particles in crystalline solids are arranged in a short range as well as long range order yet crystals are not perfect.
They possess small crystals have defects that are irregularities in the arrangement of constituent particles in them when crystallization process occurs at fast or moderate rate.
o These defects are of two types- point defects and line defects.
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The irregularities or deviations from ideal arrangement around a point or an atom in a crystalline substance.
The irregularities or deviations from ideal arrangement in entire rows of lattice points are known as line defects.
o These irregularities are called crystal defects.
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Point defects can be classified into three types:( i) stoichiometric defects( ii) impurity defects and( iii) non-stoichiometric defects
Stoichiometric Defects
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These ranges of point defects do not disturb the stoichiometry of the solid.
o They are also called intrinsic or thermodynamic defects.
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Non-ionic solids exhibit their defects as vacancy defects and interstitial defects.
Vacancy Defect:
A crystal containing vacant lattice sites is said to have vacancy defect. This defect can also develop due to heating up of a substance.