G interstitial anion in MG

This reaction starts from the weakly adsoibed G gas and creates G ions in interstitial positions in MG. It refers to reaction [2.R.11]. It 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 strongly adsorbed ion G in interstitial position in MG, which causes the release of a new site x of chemisorption and destroys the 

The two preceding steps consider an equivalent reaction (see section 7.9) that can be written as  

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