Question

What kind of point defect is produced when $AgCl$ is doped with $CdC{l_2}$?

Answer 1

We must know about point defects. Therefore, we can define a point defect as a place in the crystal lattice from where an atom is missing or is in an irregular place. And also we must know the ion formed by $Ag$ is $A{g^ + }$ and the ion formed by $Cd$ is $C{d^{2 + }}$.

Complete answer:
Point defect includes the following: self-interstitial atoms, interstitial impurity atoms, substitutional atoms, and vacancies.
A self-interstitial atom is the one that crowded its way inside the crystal lattice. It is an extra atom and only happens in a low concentration of metals because they distort and are under high stress.
An interstitial impurity atom is an atom that is smaller than the atoms which form the lattice. This atom gets placed in between the void formed by these big atoms.
Substitutional atoms are the one which have almost similar size as that of atoms forming lattice but are of a different element. These atoms displace the atom in the lattice and place itself in its place.
Vacancies are the spaces where an atom should be placed but are missing.
Now, when $AgCl$ is doped with $CsC{l_2}$ two $A{g^ + }$ions are replaced by one $C{s^{2 + }}$ ions and due to this cation vacancies are being formed.
Hence, cation vacancy defect a type of vacancy defect happens.

Note:
We must know that point defects not only affect the structure of the lattice (by distorting the lattice) but also changes the property of the compound. That’s the reason why the alloys are having different properties than their parent elements. Some alloys become more malleable, ductile, strong while some lose their strength and all. All these happen due to the defects that are being generated in the lattice which brings up some new properties.