Spin only magnetic moment of an octahedral complex of $\mathrm{Fe}^{2+}$ in the presence of a strong field ligand in BM is :

JEE Main · 2021 · 20 Jul 2021 · Shift 2 · Coordination Compounds

Spin only magnetic moment of an octahedral complex of

Fe^{2 +}

in the presence of a strong field ligand in BM is :

(A)2.82
(B)3.46
(C)0✓ Correct
(D)4.89

Answer: (C)

Solution

F e^{2 +}

is a

3 d^{6}

ion. A strong field ligand makes the octahedral splitting

Δ_{o}

larger than the pairing energy, so all six electrons occupy the lower

t_{2 g}

set as three pairs and the

e_{g}

set stays empty. With no unpaired electron,

n = 0

and

μ = n (n + 2) = 0

BM.

JEE Main · 2021 · 20 Jul 2021 · Shift 2 · Single correct option

Practise more: all JEE Main PYQs on Coordination Compounds →

More JEE Main questions on Coordination Compounds

Given below are two statements:

Statement I: Among $[Cu (NH_{3})_{4}]^{2 +}$ , $[Ni (en)_{3}]^{2 +}$ , $[Ni (NH_{3})_{6}]^{2 +}$ and $[Mn (H_{2} O)_{6}]^{2 +}$ , …
JEE Main 2026View solution →
Consider the transition metal ions $Mn^{3 +}, Cr^{3 +}, Fe^{3 +}$ and $Co^{3 +}$ and all form low spin octahedral complexes. The correct decreasing order of unpaired electrons in their respective d-orbitals of the complexes is
JEE Main 2026View solution →
A first row transition metla (M) does not liberate $H_{2}$ gas from dilute HCl .1 mol of aqueous solution of $MSO_{4}$ is treated with excess of aqueous KCN and then $H_{2} S (g)$ is passed through the solution. The amount of MS …
JEE Main 2026View solution →
Given below are two statements:

Statement I: Crystal Field Stabilization Energy (CFSE) of $[Cr (H_{2} O)_{6}]^{2 +}$ is greater than that of $[Mn (H_{2} O)_{6}]^{2 +}$ .

Statement II: Pot …
JEE Main 2026View solution →
Identify the metal ions among $Co^{2 +}$ , $Ni^{2 +}$ , $Fe^{2 +}$ , $V^{3 +}$ and $Ti^{2 +}$ having a spin-only magnetic moment value more than 3.0 BM. The sum of unpaired electrons present in the high spin octahedral complexes formed by thos …
JEE Main 2026View solution →
$[Ni (PPh_{3})_{2} Cl_{2}]$ is a paramagnetic complex. Identify the INCORRECT statements about this complex.
A. The complex exhibits geometrical isomerism.
B. The complex is white in colour.
C. The calculated spin-only magnetic moment of the complex is 2. …
JEE Main 2026View solution →