Formation of structural point defects

The formation of structural defects can take place inside the crystal matrix itself or it can require the surface structural elements these elements are likely to establish equilibriums with the gaseous phase. 

The only way to cause a point defect in a crystal lattice is to imagine the jump of an element from a regular position into an interstitial positioa This jump allows the formation of an interstitial element as well as a vacancy. In the case of a cationic element, we have a positive effective charge in interstitial position A° associated 

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