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pollycampos
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Homework Statement
Calculate the theoretical lattice energy for MgF2 (Born-Landé equation)
Ionic radius Mg+2 (coordination number 6) = 86 pm
Ionic radius F- (coordination number 3) = 116 pm
Madelung constant = 2.408
n = 7
Homework Equations
The Attempt at a Solution
I'm having problems with this equation, because its result is very different from the experimental lattice enthalpy of MgF2 (-2962 kJ/mol), and it must be similar.
http://img411.imageshack.us/img411/4670/quiqui.jpg
What's wrong? Maybe the sum of ionic radius? (I added the Mg ionic radius plus 2 times F radius).
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