I've just come across a problem and the equation within this problem isn't entirely explained in the text. I've searched on the net for this same 'lattice energy' equation, but there have been no results.(adsbygoogle = window.adsbygoogle || []).push({});

Here is the equation:

[tex] E = Aexp^ \frac{-r} { \alpha} - \frac{Me^2} {4 \pi \epsilon_0 r}[/tex]

Here is the question that the equation came from:

The lattice energy, E, per ion of LiF may be written in the form [tex] E = Aexp^ \frac{-r} { \alpha} - \frac{Me^2} {4 \pi \epsilon_0 r}[/tex], where M is the Madelung constant, e is the electronic charge, r is the separation of neighbouring ions and A and [tex]\alpha[/tex] are constants. Calculate E for LiF. (M=1.75, [tex]\alpha[/tex] = 0.02 nm; lattice parameter of LiF = 0.4 nm.

Anyway I was wondering if anyone knew what the first exponential equation was and if they could tell me what the constant A is?? Is it calculated using any of the given values above or something??

EDIT: Well I know that I have to calculate it now, but I have no idea what this constant is called or where it comes from. Thanks anyway guys :)

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# Homework Help: Lattice energy

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