CHF3 vs CHI3

[106467553]

In class we went over how CHI3 had a greater melting point than CHF3. F is more electronegative than I is. Does CHI3 have stronger than london dispersion forces because I is bigger than F, and that holds more value than electronegativity? Hope this question makes sense.

[506198813]

Yes, CHI3 has stronger LDF than CHF3 because Iodine is larger and more polarizable than Fluorine, which allows for stronger temporary dipoles. Although F is more electronegative, the size and polarizability of I outweigh this. Therefore, there is a higher melting point for CHI3.