Question

What is true for $\left[Fe\right(CN{)}_6{]}^{3-}$ and $[Fe{F}_6{]}^{3-}$ :

• A. Both are paramagnetic.
• B. Only $\left[Fe\right(CN{)}_6{]}^{3-}$ is paramagnetic.
• C. Only $[Fe{F}_6{]}^{-3}$ is paramagnetic.
• D. Both are diamagnetic.

Answer 1

The correct option is A Both are paramagnetic.

Both $Fe(CN{)}_6{]}^{3-}$ and $[Fe{F}_6{]}^3$ are $d^5$ complexes.
$\left[Fe\right(CN{)}_6{]}^3$ is a low spin complex and contains one unpaired electron. Hence it is paramagnetic.
$[Fe{F}_6{]}^{3-}$ is a high spin complex and contains 5 unpaired electrons. Hence it is paramagnetic.