Question

The magnetic moments of complex given below are in order

I. $\left[ Ni ( CO )_{4}\right]$

II. $\left[ Mn ( CN )_{6}\right]^{4-}$

III. $\left[ Cr \left( NH _{3}\right)_{6}\right]^{3+}$

IV. $\left[ CoF _{6}\right]^{3-}$

• A. I > II > III > IV
• B. I < II < III < IV
• C. IV > II > I > III
• D. IV < II < I < III

Answer 1

Answer: (B)

Magnetic moment $\mu =\sqrt{n \left(\right. n + 2 \left.\right)}B.M.$

n = unpaired electrons.

$n =$ unpaired electrons.

I. $\left[ Ni ( CO )_{4}\right] n =0$, so $\vec{\mu}=0 BM$

II. $\left[ Mn ( CN )_{6}\right]^{4-} n =1$, so $\vec{\mu}=\sqrt{3} BM$

III. $\left[ Cr \left( NH _{3}\right)_{6}\right]^{3+} n =3$, so $\vec{\mu}=\sqrt{15} BM$

IV. $\left[ CoF _{6}\right]^{3-} n =4$, so $\vec{\mu}=\sqrt{24} BM$

Order of magnetic moment is $I < II < III < IV$.