Question

Find the Kroger-Vink notations for point defects (Vacancies, Interstitials, Anti-site Defect) with appropriate charges for CsCl crystal. By using the Kroger-Vink notation, list a Schottky defect pair and a Frenkel defect pair for CsCl.

Answer 1

Kröger-Vink Notation:

X – nature of species located on a site: element symbol for an atom, V for vacancy

Y – type of the site occupied by X: (i for an interstitial, element symbol for site normally occupied by this element)

Z – charge relative to the normal ion charge on the site ′ negative relative charge • positive relative charge x zero relative charge (x is often omitted)

For CsCl it can be given as

Vaccancy on a Cs site in CsCl :V'_Cs

interstitial Cs ion in CsCl: Cs_i^.

Frenkel defect pair in CsCl: Cs^x_Cs-->Cs_i^. + V'_Cs

Schottky defect pair in CsCl : Cs^x_Cs+Cl^x_Cl -->V'_Cs + V'_Cl+ Cs^x_Cs+Cl^x_Cl