Question

Which of the following is paramagnetic?

• A. \([\mathrm{Fe(CN)_6}]^{4-}\)
• B. \([\mathrm{Ni(CO)_4}]\)
• C. \([\mathrm{Ni(CN)_4}]^{2-}\)
• D. [CoF₆]³-

Hint:

Weak ligands produce high-spin, paramagnetic complexes.

Answer 1

The Correct Option is D

Step 1: Co³+ has d⁶ configuration.
Step 2: F⁻ is a weak field ligand → high spin complex.
Step 3: Presence of unpaired electrons → paramagnetic.