Question A3 Sodium tantalate, NaTaO3, has the cubic perovskite structure above 890 K. When cooled below this temperature, it undergoes a phase transition. Predict the type of geometric distortion that will occur at this transition, given the ionic radii Na* = 1.32 Å, Ta5+ = 0.78 Å, O²- = 1.25 Å.

Question A3 Sodium tantalate, NaTaO3, has the cubic perovskite structure above 890 K. When cooled below this temperature, it undergoes a phase transition. Predict the type of geometric distortion that will occur at this transition, given the ionic radii Na* = 1.32 Å, Ta5+ = 0.78 Å, O²- = 1.25 Å.