Which complex among the following has the highest value of spin only magnetic moment? ( [ Fe ( CN )₆ ]³⁻, [ Fe ( CN )₆ ]⁴⁻, [ Ni ( CN )₄ ]²⁻ ), ( [ NiCl ₄ ]²⁻ )

Step-by-step solution

(a) ( [ Fe ( CN )₆ ]³⁻ ) has (d^2 s p^3 ) (inner (d ) - complex) hybridisation with one electron unpaired. (b) The ( Fe ²⁺ ) ion in ( [ Fe ( CN )₆ ]⁴⁻ ) has outer electronic configuration of (3 d^6 ). The complex is a low spin complex. It contains 0 unpaired electrons with magnetic moment of (0 BM ) Therefore, under the influence of the octahedral crystal field, the possible electronic arrangement of ( Fe ) (II) ion is (t_ 2 g ^6, e_g^0 ). (c) ( [ Ni ( CN )₄ ]²⁻ ) is a square planar geometry formed by (d s p^2 ) hy