In which of the following complexes the CFSE, Δ 0 will be equal to zero?

Chemistry · Coordination Compounds

JEE Main 2025 — 22 January, Morning Shift — Question 40

In which of the following complexes the CFSE, $\Delta_{0}$ will be equal to zero?

Option A:
$\left[\mathrm{Fe}\left(\mathrm{NH}_{3}\right)_{6}\right] \mathrm{Br}_{2}$
Option B:
$\left[\mathrm{Fe}(\mathrm{en})_{3}\right] \mathrm{Cl}_{3}$
Option C:
$\mathrm{K}_{4}\left[\mathrm{Fe}(\mathrm{CN})_{6}\right]$
Option D:
$\mathrm{K}_{3}\left[\mathrm{Fe}(\mathrm{SCN})_{6}\right]$
Correct

For complex $\mathrm{K}_{3}\left[\mathrm{Fe}(\mathrm{SCN})_{6}\right]$

Calculation of CFSE

$=(-0.4 \times 3+0.6 \times 2) \Delta_{0}$

$=0 \Delta_{0}$

Answer key and solution verified before publishing.

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