Lattice Enthalpy of Formation

\Delta_{L}H^{\circ}=\frac{C\cdot z^{+}\cdot z^{-}\cdot v}{\left(r^{+}+r^{-}\right)}-2.5v

Where:

• C is a constant approximately equal to 105000 units;

• z+ and z− are the signed charges on the cation and anion respectively in units of e;

• ν is the number of ions in the formula (e.g. 3 for MgI2​);

• r+ and r− are the radii of the ions in pm;

• The −2.5ν term corrects for the difference between internal energy and enthalpy.