Question

why pentahalides are more covalent than trihalides??( group 15)

Answer 1

Dear Student
According to the Fajan's rule, if the charge on the cation is higher, its polarisability will be higher and then its covalent character will be higher.
In the case of metal Penta halides (MX₅), metal cation will have +5 charge while in trihalides (MX₃), the metal cation will have +3 charge so the Pentahalides(MX₅) will have more polarizability and hence more covalent character so the pentahalides are more covalent than trihalides.


Regards.