Question

The spin-only magnetic moment value for the complex [Co(CN₆)]^4- is ______ BM. [At. no. of Co = 27]

Options

• 3.69

• 2.05

• 4

• 1.73

Answer 1

The spin-only magnetic moment value for the complex [Co(CN₆)]^4- is 1.73 BM.

Explanation:

[Co(CN₆)]^4- 

x + 6 × (- 1) = - 4

x = ± 2

CO²⁺ : [Ar] 3d⁷

and CN^- is a strong field ligand which can pair electrons of the central atom.

Transference of electrons

It has one unpaired electron (n) in the 4d - subshell. So spin only magnetic moment (μ) = `sqrt("n"("n + 2"))` BM

where n = number of unpaired electrons.

`mu = sqrt3` BM

μ = 1.73 BM