The Fluorite and Rutile Structures

As seen from the diagram, the heat of sublimation of sodium metal is S, the ionization potential of sodium is 7, the heat of dissociation of CU is Z , the electron affinity of Cl is EA and the lattice energy (crystal energy) is designated by Exattice. The heat given off in the entire reaction, (often designated as Q) would be  

Perhaps one of the most interesting applications of electron affinities and the Born-Haber treatment is the calculation of stabilities of odd molecules such as NeF, NaF2, and CaF (Exercises 15-17). 

The three structures already described (the zinc blende, sodium chloride, and cesium chloride arrangements) must of necessity be confined to compounds of simplest formula AiCv The two most important type structures for compounds of type, AC2 (or A2C), are the fluorite (CaF2) and rutile (Ti02) structures. 

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The Fluorite and Rutile Structures.—Compounds of the type MXS also have their choice of two ionic structures, but the factors influencing them... 

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