Q2(b). Equilibrium vacancy concentration
Derive an expression to calculate the number of vacancies per mole of metal atoms at a given temperature. Assume (i) vibrational entropy is small and can be neglected, and (ii) Eᵥ is the energy required to create one mole of vacancy.
Answer in brief
In the dilute-vacancy limit, the number of vacancies per mole of metal atoms is nᵥ ≃ NA e−Eᵥ/RT.
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CoversSchottky defectvacancy concentrationconfigurational entropyStirling approximationpoint defects in metals
All parts of Question 2
- 2(a) Most probable radius in Li²⁺10 marks
- 2(b) Equilibrium vacancy concentration15 marks
- 2(c) Arrhenius parameters from a logarithmic law10 marks
- 2(d) Ordering metal reduction potentials5 marks