Impurity defect
- Crystallization of molten NaCl with little amount of SrCl2 results in Sr2+ occupying some of the sites of Na+
- Each Sr2+ replaces two Na+ ions.
- It occupies the site of one ion and the other site remains vacant.
- The cationic vacancies thereby produced are equal in number to that of Sr2+
- Solid solution of CdCl2 and AgCl.
