Melting points and size?

Question

So I'm kind of lost. I must explain why the melting point of NaF is 993 degrees Celcius while the m.pt. of CsCl is 645 degrees Celcius. From what I understand NaF is smaller than CsCl. But, the dispersion forces are stronger between larger molecules. I don't understand why the melting point is higher for the smaller molecule. Could you please explain?

But my teahcer said to look at size

Answer 1

I suggest you look at the bond strength not the lattice size.