Examine the given defective crystal :

 

X+     Y-    X+     Y-   X+     Y-  X+    

            X+

 Y-    O     Y-   X+     Y-  X+     Y- 

 

X+     Y-    X+     Y-   X+     Y-  X+    

 

Y-    X+     Y-   X+     Y-  X+     Y- 

Answer the following questions :

(a) Is the above defect stoichiometric or non stoichiometric ?

(b) Write the term used for this type of defect.

(c) Why do silver halides show this type of defect ?

Asked by santrarindam2002 | 19th Jun, 2018, 10:34: AM

Expert Answer:

(a) It is a stoichiometric defect.
 
(b) It is a Frenkel defect. In this an ion is missing from its correct lattice site and occupies interstitial site
      so the stoichiometry of the compound is maintained.
 
(c)  Silver halides show this type of defects because the size of Ag+ is similar to the size of voids.
       So the Ag+ ions can move to the interstitial sites.

Answered by Varsha | 19th Jun, 2018, 06:39: PM