Born haber cycle

• Born håber example steps for lithium chloride

  1. Enthalpy of atomisation of chlorine (endothermic)
  2. Enthalpy of atomisation of lithium (endothermic)
  3. 1st ionisation energy for lithium (Endothermic)
  4. 1st electron affinity for chlorine (exothermic)
  5. Lattice enthalpy of formation of lithium chloride (Exothermic)
• Born Haber sodium chloride

  sodium chloride

  A) First ionisation energy of sodium

  B) atomisation enthalpy of sodium

  C) atomisation enthalpy of chlorine

  D) 1st electron affinity of chlorine

  E) lattice enthalpy of formation for sodium chloride

  
• Calculating lattice formation


  s: calculate enthalpy changes for ionisation of atoms, bond dissociation, atomisation, electron affinity and formation of 1 mole of solid crystal from gaseous ions. The sum of all these changes equals lattice enthalpy.
• Born håber cycles extended: e.g MgO (S)

  1. Mg (s) + O2 (g)
  2. Mg (s) + 2O (g)
  3. Mg (g) + 2O (g)
  4. Mg+ (g) + 2O (g) + e-
  5. Mg 2+ (g) + 2O (g) + e- (2nd ionisation step to create Mg2+)
  6. Mg 2+ (g) + O - (g) + e-
  7. Mg 2+ (g) + O 2- (g) (2nd electron affinity, O- to O2- ion)