Experimental proof of magnetic measurements supports the concept of high- and also low-spin complexes. Remember that molecules such together O2 that contain unpaired electrons room paramagnetic. Paramagnetic substances room attracted come magnetic fields. (see video)

Many shift metal complexes have unpaired electrons and hence are paramagnetic. Molecule such as N2 and also ions such together Na+ and 4− the contain no unpaired electrons are diamagnetic. Diamagnetic substances have actually a slight tendency to it is in repelled by magnetic fields.

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When an electron in one atom or ion is unpaired, the magnetic moment due to its spin makes the entire atom or ion paramagnetic. The size of the magnetic minute of a device containing unpaired electron is directly related come the variety of such electrons: the higher the number of unpaired electrons, the bigger the magnetic moment. Magnetic susceptibility steps the pressure experienced by a substance in a magnetic field. Once we to compare the weight of a sample come the load measured in a magnetic field (Figure (PageIndex1)), paramagnetic samples that room attracted come the magnet will appear heavier due to the fact that of the force exerted by the magnetic field. We have the right to calculate the variety of unpaired electrons based on the rise in weight.


(PageIndex1): A Gouy balance compare the mass of a sample in the visibility of a magnetic field with the mass with the electromagnet turned off to determine the variety of unpaired electrons in a sample. Image used through permission (CC BY-SA 3.0; OpenStax).

From this experiment, the measure up magnetic moment of low-spin d6 4− ion confirms the iron is diamagnetic, conversely, the high-spin d6 2+ complicated has 4 unpaired electrons v a magnetic moment that confirms this arrangement. Therefore, the it was observed magnetic moment is used to recognize the variety of unpaired electron present.

Magnetic nature of Coordination Compounds

An amazing characteristic of shift metals is their capability to kind magnets. Metal complexes that have actually unpaired electrons space magnetic. Because the critical electrons reside in the d orbitals, this magnetism must an outcome fromunpaired d electrons. Considering just monometallic complexes, unpaired electrons arise due to the fact that the complex has one odd number of electrons or due to the fact that electron pairing is destabilized. For example, the Ti(III) ion has actually one d electron and also must it is in (weakly) paramagnetic, nevertheless of the geometry or the nature of the ligands. However, the Ti(II) ion with two d-electrons, sometimes creates complexes through two unpaired electrons and also sometimes develops complexes v no unpaired electrons.

As one example, Fe3+ has five d electron prefers octahedral geometry. The complex3-is high-spin (d^5) and is attracted strongly to magnetic fields;however, (^3-) is low-spin (d^5) andonly has one unpaired electron, making it a weaker magnet. This trend have the right to be explained based on the nature of the ligands.

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The zinc ion in (Cl_2) has actually a +2 oxidation state andis a d10. This is a diamagnetic compound. The stole ion in (K) has actually a +3oxidation state andis d5.It just has four electrons and is an ext likely to it is in in atetrahedral geometry 보다 square planar. Because that tetrahedral geometries, we mean high spin; further, it has actually weak-field ligands.This compound will certainly be paramagnetic (with 5 unpaired electrons). The cadmium ion in (SO_4) has a +2 oxidation state, and also isd10. This is a diamagnetic compound.