Question

The bond length in $CO$ is $1.128\dot{A}$. What will be the bond length of $CO$ in $Fe{\left(CO\right)}_5$?

• A. $1.158\dot{A}$
• B. $1.128\dot{A}$
• C. $1.078\dot{A}$
• D. $1.118\dot{A}$

Answer 1

The correct option is A $1.158\dot{A}$

• In $Fe(CO{)}_5$ there exists a synergic bond between $Fe$ and $CO$. Due to synergic bond formation between metal and $CO$, the bond order of $CO$ decreases.
  
• As bond order decreases the Bond length increases.Here the only option having greater bond length than $1.128A^0$ is option A- $1.158A^0$.
• Hence, option $A$ is the correct answer.