2.12.1.2 Case II: If interstitial metal or metal excess is present

Here, the defect reaction will be

The equilibrium constant can be written as

(2.34)

Both [M_M] and [O_O] can be assumed to be ~1 if [M_i^••] << [M_M] and [O_O].

According to the electrical neutrality condition

Thus

OR

ne

(2.36)

The plot will be similar to that of the above case.