G vacancy anion in MG

This reaction also occurs on the interface between MG and a solid containing M and refers to reaction [2.R.18]. This creation also involves two jumps and therefore two elementary steps. 

The voluminal speed of this elementary step can be written as (defects being diluted)  

The second jump is that of the ion in normal position in the vicinity of the new cation, which causes the release of the electron (except if the normal MG defect is not ionized). This jump is schematized in Figmes 4.7b and c and can be written as  

It should be noted that the second phase, as well as the whole process, creates a new MG building unit and thus increases the size of the formed solid. 

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