Mol% TiO2 is mixed to 99.9 mol% Al2O3 and reacted to form a non-stoichiometric homogeneous solid solution. (3 pt)

(a) Write 3 defect reactions (all TiO2 atoms go into regular sites; all anions go into regular sites; all cations go into regular sites)

(b) Addition of TiO2 to Al2O3 generates defects. Calculate the net variation of mass for each of reactions in (a) in reation to perfect Al2O3 by considering the result of the defect reaction, e. g., Ti substituting for Al (gain of mass mTi – mAl =). Which reaction generates the highest net gain of mass ?

(c) For each defect reaction, write the chemical formula of the solid solution.