MgO adopts the NaCl-type structure with a = 4.22 . (a) Use the BornMayer equation to calculate the lattice-formation energy for MgO. (b) Given this

MgO adopts the NaCl-type structure with a = 4.22 Å.

(a) Use the Born–Mayer equation to calculate the lattice-formation energy for MgO.

(b) Given this estimate of the lattice energy, construct a Born–Haber cycle and estimate the second electron gain enthalpy of oxygen, O⁻ (g) + e⁻ → O²⁻ (g). Sublimation enthalpy of Mg = +147 kJ/mol, bond dissociation energy of dioxygen = 498 kJ/mol, first ionization energy of Mg = 738 kJ/mol, second ionization energy of Mg = 1451 kJ/mol, first electron gain enthalpy of oxygen = −141 kJ/mol, enthalpy of formation of MgO = −602 kJ/mol.