Which of the following has magnetic moment value of 5.9?

Fe2+ Fe3+ Mg2+ Zn2+

Fe3+

Fe3+ has a magnetic a magnetic moment value of 5.9. 26Fe : [Ar]4s23d6 Fe3+ : [Ar]3d5 Magnetic moment, u = \(\sqrt {n(n+2)}\) u = \(\sqrt {5(5+2)}\) = \(\sqrt {35}\) = 5.9