Subject: Inorganic Chemistry · Chapter: Organometallic Compounds · Topic: Organometallics – General · Exam: JAM 2005-2022 · Marks: 2 · Difficulty: Hard
The order of increasing CO stretching frequencies in $\left[\mathrm{Co}(\mathrm{CO})_{4}\right]^{-},\left[\mathrm{Cu}(\mathrm{CO})_{4}\right]^{+},\left[\mathrm{Fe}(\mathrm{CO})_{4}\right]^{2-}$ and $\left[\mathrm{Ni}(\mathrm{CO})_{4}\right]$ is