Born-Haber Cycle (Enthalpy of Formation)

$$\Delta H_f = \Delta H_{\text{sub}} + \text{I.E.} + 0.5 \cdot \Delta H_{\text{diss}} + \text{E.A.} + U$$

Concept: An application of Hess's Law that breaks down the overall thermodynamic enthalpy change of ionic compound formation into individual elemental steps.

Notation:

• $$\Delta H_f$$ = Enthalpy of formation;
• $$\Delta H_{\text{sub}}$$ = Enthalpy of sublimation;
• $$\text{I.E.}$$ = Ionization energy;
• $$\Delta H_{\text{diss}}$$ = Bond dissociation energy;
• $$\text{E.A.}$$ = Electron affinity;
• $$U$$ = Lattice energy.