It would be.. sand, slit, clay.
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 .
