Question

PROBLEMS 3.1 When CaO is dissolved in ZrO2, oxide ion vacancies are created on the zirconia lattice. Calculate the fraction of oxide ion sites that will be vacant when one mole percent of calcium oxide is added to (i.e., dissolved in) the zirconia. Neglect the intrinsic oxide ion vacancies. What is the oxide ion vacancy concentration stated at vacancies per cubic centimeter? The density of zirconia is about 5.5 g/cm'.

Answer 1

The fraction of oxide ions that could be left vacant when 1 mol% of CaO is added to ZrO2 = 0.01*1/2 = 0.005

The oxide ion vacancy concentration = 0.005 * 5.5 g/mL * 1000 mL/1 L * 1/123.222 g.mol^-1 = 0.2232 mol/L or 0.2232 M

Note: 1 cm³ = 1 mL, 1 L = 1000 mL