The spin only magnetic moment of Fe ³⁺ ion (in BM) is approximately.

Step-by-step solution

Electronic configuration of Fe . aligned ₂₆ Fe & =[ Ar ] 3 d^6 4 s^2 Fe ³⁺ & =[ Ar ] 3 d^5 aligned Number of unpaired electrons, n=5 Spin only magnetic moment, _s= n(n+2) BM gathered _s= 5(5+2) _s= 35 _s=5.85 BM or _s 6 BM gathered