Paramagnetism: Oxidation States of Manganese - Manganese (III) Oxide

Manganese(III) oxide is paramagnetic and is strongly attracted to a magnet.

Manganese(III) oxide, with 4 unpaired electrons per Mn atom, is more strongly attracted to a magnet than is manganese(IV) oxide, with only 3 unpaired electrons per Mn atom. Potassium permanganate, a compound of Mn(VII), has no unpaired electrons and is not attracted to a magnet.

Discussion: 

Substances containing unpaired electrons are usually paramagnetic. In the presence of a magnetic field the spins of the unpaired electrons are aligned and the substance is attracted by the magnetic field. Since Mn2O3 has a high spin d4 electron configuration, it is more strongly attracted by the magnet than MnO2, with a d3 electron configuration. Since MnO4 contains Mn(VII) with a d 0 configuration, it is diamagnetic (no unpaired electrons). Diamagnetic substances are weakly repelled by a magnetic field, but the effect is too small to be observed without a much stronger magnet than the one used here.

Credits: 
  • Design and Demonstration
    • George Lisensky Beloit College, Beloit, WI 53511
  • Text
    • George Lisensky Beloit College, Beloit, WI 53511
    • Nancy S. Gettys University of Wisconsin - Madison, Madison, WI 53706
    • David Phillips Wabash College, Crawfordsville, IN 47933
  • Video
    • Jerrold J. Jacobsen University of Wisconsin - Madison, Madison, WI 53706