Question

Phosphorus forms pcl5 but nitrogen does not forms ncl5 why

Answer 1

Phosphorus can form phosphorus pentachloride due to the presence of a vacant 3d orbital.

• Phosphorus contains a vacant 3d orbital and the electron of the 3s orbital can expands to a 3d orbital and give five coordinated phosphorus pentachlorides.
• Nitrogen is small in size and does not contain a d orbital so, the electrons of 2s can not move to the d orbital and do not form five coordinated nitrogen pentachlorides. Again the small size of the N atom also disfavours the five coordination.