Values of Born Exponent to be Used in Repulsive Function for Lattice Energy*

Ion TypeExamplen
He-He LiH 5
Ne-Ne NaF, MgO 7
Ar-Ar KCl, CaS, CuCl 9
Kr-Kr RbBr, AgBr 10
Xe-Xe CsI 12

*For compounds of mixed ion types, use the average value (e.g., for NaCl, n = 8).

Reference: Huheey, pps. 99-134.