The Born-Haber Cycle for Ionic Crystals

Although the condensation of isolated ions to form a crystal lattice is not a chemically important process, the lattice energies may be used, in conjunction with other data, to determine other quantities of greater interest. 

The electron affinities of elements (Chap, 7) that form negative ions may be calculated by considering the formations of compounds containing such negative ions. The formation of such a compound from the elements (the heat of such a reaction being directly measurable) may be broken down into a series of simpler steps. The treatment is again called a Born-Haber cycle and is analogous to the treatment of the conversion of an alkali metal to its hydrated ion (discussed in Chap. 6). Consider the formation of sodium chloride from the elements  

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