The cluster types of $\left[\mathrm{Fe}_{5}(\mathrm{CO})_{14} \mathrm{N}\right]^{-}$and $\left[\mathrm{Co}_{6}(\mathrm{CO})_{13} \mathrm{N}\right]^{-}$are, respectively,
(a)nido-, nido
(b)nido-, closo
(c)closo-, nido
(d)closo-, closo
Answer
Answer: B ✓ checked by 4AB · confidence high
Explanation
[Fe₅(CO)₁₄N]⁻: 74 e, 7 skeletal pairs for 5 vertices (n + 2) — nido; [Co₆(CO)₁₃N]⁻: 86 e, 7 pairs for 6 vertices (n + 1) — closo (b).