Answer: Metal deficiency defect.
- A Schottky defect
- B Frenkel defect
- C Metal deficiency defect
- D Interstitial defect
Correct answer: C. Metal deficiency defect
Explanation: In FeO, some Fe²⁺ are replaced by Fe³⁺; fewer total iron atoms are needed to balance the oxygen, creating a metal-deficiency (non-stoichiometric) defect.
The three cubic unit cells: Simple Cubic has atoms only at corners; Body-Centred adds one atom at the centre; Face-Centred adds one atom at the centre of each of the 6 faces, giving the highest packing efficiency.
Concept context
Explore the ordered world of crystalline solids: unit cells, packing, defects, and how structure determines electrical and magnetic properties.