The Coulomb interaction energy of two polarized ions at distance

15 The Coulomb interaction energy of two polarized ions at distance R 

The total Coulomb energy of the ion pair may be written as the sum of four terms  

In Fig. 5.6 we represent the induced dipole moment on the anion as two charges, +q and -q separated by a small distance r. Note that the cation is situated on the line through these charges and closer to the negative than to the positive pole. 

GASEOUS ALKALI METAL HALIDES IONIC BONDS 

The energy due to attraction between the cation and the induced dipole moment on the anion may be calculated as follows  

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