Q2(c). Void fraction with one octahedral occupant
In a face-centred unit cell with all the positions occupied by A atoms, the body-centred octahedral hole in it is occupied by an atom B of an appropriate size. Calculate the void space per unit volume of unit cell for such a crystal.
Answer in brief
For touching A spheres and the largest B sphere that fits the body-centre hole, the unoccupied volume fraction is approximately 0.2464 (24.64%).
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CoversFCC unit celloctahedral voidpacking fractionvoid spaceradius ratio
All parts of Question 2
- 2(a) Particle in a one-dimensional box15 marks
- 2(b) Dissociation of an ionic KF molecule10 marks
- 2(c) Void fraction with one octahedral occupant15 marks