ionic vs. covalent bonding

[Abby De La Merced 3F]

I know that in lecture we learned that if the electronegativity difference is greater than two than there is an ionic bond and if the different is less than 1.5 then there is a covalent bond but what if the electronegativity difference is in the .5 between 1.5 and 2?

[jessicahe4Elavelle]

Doctor Lavelle says that in these cases we cannot determine directly whether the two atoms will engage in covalent or ionic bonding through that simple rule, and we have to look at the specific cases.

[005199302]

The rule does not apply for those cases.