The chemical formula of ferrocene is:

Finely divided iron combines with $CO$ to give

The correct pair of orbitals involved in $\pi$-bonding between metal and $CO$ in metal carbonyl complexes is

The structure of ferrocene is $Fe(\eta ^5 - C_5H_5)_2$.

The bond length of the $C-O$ bond in carbon monoxide is $1.128 \ \mathring{A}$. The $C-O$ bond length in $Fe(CO)_5$ is ............. $\mathring{A}$.

Which statement is true for ferrocene?