In \(\left[ MnCl _4\right]^2: d^5\) configuration and \(5\) unpaired electrons
In \(\left[ CoCl _4\right]^2: d^7\) configuration and \(3\) unpaired electrons
In \(\left[ Fe ( CN )_6\right]^4: d ^6\) configuration, low spin complex and o unpaired electrons
More the number of unpaired electrons, more the value of magnetic moment.
Hence, the order is \(\left[ MnCl _4\right]^{2-} > \left[ CoCl _4\right]^{2-} > \left[ Fe ( CN )_6\right]^{4-}\)
(નોંધ : યુગ્મીકરણ ઊર્જા અવગણો)
$(I)$ $K[Co(NH_3)_2(NO_2)_4$ $(II)$ $[Cr(NH_3)_3(NO_2)_3]$ $(III)$ $[Cr(NH_3)_5NO_2]_3[CO(NO_2)_6]_2$ $(IV)$ $Mg[Cr(NH_3) (NO_2)_5]$