Question

The C-O stretching frequency of carbon monoxide changes when the molecule coordinates to a metal centre. Does it increase or decrease? Explain

Answer 1

Answer:

decrease

Explanation

During the co ordinate bond between the Carbonyl and The metal ,

The Carbonyl donates the sigma electrons and through the process of back bonding , it accepts the electrons in its pi star orbitals i.e. , the antibonding orbitals , thereby reduces the bond order and which in turns reduces the bond strength and , there fore ,

The IR stretching frequency for CO reduces .