Magnetic Susceptibility

Equipment

5 kilogauss magnet, ring stand with wood or aluminum rod clamped on top, thread with loop at end affixed to rod, small test tubes with hook in each stopper for string attachment.
Additionally, a digital balance with a minimum accuracy of 0.1 g and a hook below the pan may be used.

Reagents

SiO₂, KNO₃, Na₂SO₄, CoCl₂, NiSO₄, NiCl₂, MnO₂, Fe₂O₃, Fe₃O₄, NH₄VO₃, KMnO₄, K₂Cr₂O₇, Cu, Co(NH₃)₆Cl₃, Na₃FeF₆, Cr₂O₃, (NH₄)₂SO₄· FeSO₄, Iron nails, Co(NH₃)₄Cl₂Cl.

Presentation

1. Remove keeper from magnet. Force keeper down with thumbs, allowing the heavy disk to follow the magnet’s inner surfaces until the keeper can be removed.
2. Hang the samples on the thread. Adjust the length and height so the sample is level with the poles of the magnet. Move the magnet along the desk. The sample tube will follow the magnet or not. Describe atomic architecture of sample, note color, guess weather para- or diamagnetic, covalent or ionic bonding.
3. Alternatively, suspend the tube directly from the balance hook (out of magnetic field) and zero the balance.
4. Suspend the tube from thread so that it is in the magnetic field.
5. Note if any change in the balance reading occurs.

Hazards

Remove wrist watch. The iron nails may smash against the magnet and break the test tube.

Discussion

Paramagnetic materials contain unpaired electrons.

References

1. Tutorial Video Tape III found in Learning Resources Centers in Walter Library and St. Paul Library.