Differentiate between Frenkel and Schottky defects?

Frenkel and Schottky defects

Frankel Pairs: One such type of defect involves a cation-vacancy and a cation- interstitial pair. It might be thought of as being formed by a cation leaving its normal position and moving into an interstitial site. There is no change in charge because the cation maintains the same positive charge as an interstitial. This is called a Frankel defect.

e.g. closed packed structures have fewer interstices and Frankel defects, because additional energy is required to force the atom into a new position.

Schottky defect: The removal of a positive ion to create a vacancy must be counter balanced by the removal of a negative ion in order to maintain neutrality. The pair of vacancies is termed as schottky defect.

e.g. with a sodium chloride crystal, the removal of a positive sodium ion is balanced by the removal of a negative chlorine ion in order to maintain neutrality.