Magnetic properties of transition metals.

 Magnetic properties of transition metals.

The magnetic moment of an electron is partly due to its spin motion and partly due to its orbital motion.

The effective magnetic moment ( µ_eff ) of a substance containing an unpaired electron, is thus made up of two components,

(I)The contribution due to the orbital motion of electron, µ_orbital ,which is due to the orbital quantum number l  and

(II) The contribution due to the spin motion of the electron,µ_{spin ,} which is due to the spin quantum number S .

In transition metal ions the unpaired electrons are generally present in the outer orbitals.

The orbital motion of such unpaired electrons are severely disturbed by the electrons of the surrounding ligants,there by quenching the µ_orbital in the transition metal compounds.

Therefore,in such cases µ_spin contribution becomes much more significant than the µ_orbital contribution so that the later may be neglected in many cases.


The effective magnetic moment, µ_eff,in such cases may thus be given by the expression.

                                                             µ_eff = √n(n+2)   

Where,n is the number of unpaired electrons. The magnetic moment is expressed in Bohr magneton. A Bohr magneton  ( B.M ) is given by the expression,

                                                             B.M= eh / 4πmc

Where h is the plank`s constant, e is the electronic charge, c is the velocity of light and m is the mass of electron.

Summary :


Magnetic properties of transition metals .

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