When comparing boiling points of two ionic compounds, should you look at their electronegativity difference, lattice energy, or strength from LDF forces (or all 3 factors)?
For example, between LiCL and NaCl, which one has the higher boiling point?
If we look at EN difference and LDF forces, it would be NaCl, because the EN difference here would be $2.1$ compared to $2.0$ for LiCL; also, since Na has an extra energy level, it has a larger electron cloud and thus stronger LDF's.
However, if we look at it in term of lattice energy or Coloumb's law, LiCl has a larger boiling point because high lattice energy is a combination of large charge and small ions. Therefore, even though Li and Na have the same charge, Li has a smaller atomic radius than Na.