Question

The metal complex that is diamagnetic is (Atomic number : $Fe, 26; Cu, 29$)

• A. $K_3[Cu(CN)_4]$
• B. $K_2[Cu(CN)_4]$
• C. $K_3[Fe(CN)_4]$
• D. $K_4[FeCl_6]$

Answer 1

Answer: (A)

$K_3[Cu(CN)_4]$

Answer 2

$K_3[Cu(CN)_4]$ is diamagnetic

$Cu(I) ⇒ d^{10}$ configuration

$⇒$ No unpaired electrons.

$⇒$ $K_2[Cu(CN)_4], K_3[Fe(CN)_4] \;and \;K_4[FeCl_6]$ are paramagnetic in nature.