We know that Carbon halogen bond length increases moving from F to I (halogens) so there must be weak force of attraction in between the atoms then why is the bp of I More than that of Fluorine?

Dear Student,

The boiling point of the molecules are influenced by intermolecular forces (IMF), as we move from F to I the atomic radius increases resulting in more electrons even though atomic radii doesn't influence boiling point but their vanderwaals force formation between valence electron in heavier halogens are higher which results in requirement of more energy to break the intermolecular force to make the molecule boil, among fluorine and iodine, iodine is having higher amount of vanderwaals 
force due to their heaviness while fluorine is lighter resulting in easy lose of intermolecular forces. 

Hence fluorine boils sooner than Iodine resulting in higher boiling point for Iodine than fluorine.


  • 1
What are you looking for?