Why AgBr shows both Schottky and Frenkel defects??

Asked by vaish.agrawal | 11th Jun, 2015, 11:56: PM

Expert Answer:

AgBr shows both Frenkel and Schottky defects because the radius ratio for AgBr is intermediate.


Ions have Schottky defects when their anions and cations are both absent from the crystal lattice.

In AgBr, the Ag+ ions and corresponding Br̶̶‒ ions are absent from the crystal lattice causing Schottky defects.

However, Ag+ ions are exceptionally mobile and they have a tendency to move about inside the lattice. So they complement the Schottky defects with Frenkel defects with the Ag+ ions trapped in interstitial spaces. Because of the similar size of Ag+ ions and Br ions and the small size of Agions and the fact that Ag+ ions have a property to be mobile, both Schottky and Frenkel defects occur.

Answered by Hanisha Vyas | 12th Jun, 2015, 11:02: AM

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