Magnetic susceptibility: Gouy balance template

A long tube of powdered complex hung from a balance with its lower end between the poles of an electromagnet, powered by a DC supply; the change in apparent mass gives the susceptibility. University inorganic labs (A-level / IB extension).

What the template shows

• Weigh a sample with the magnetic field off and on to count its unpaired electrons
• Weigh with the field off, then on (constant current). Paramagnetic samples are pulled down into the field: apparent mass rises
• Gouy tube
• Packed evenly to a fixed mark with the finely ground sample, e.g. CuSO₄·5H₂O or [Ni(H₂O)₆]SO₄; top end out of the field
• Bottom of the sample in the strongest, even field between the poles
• Calibrate with a standard such as Hg[Co(SCN)₄]. χ from Δm; μeff = 2.83 √(χm T) μB ≈ √(n(n + 2)) for n unpaired electrons
• Reaction setup

Drawn with 16 shapes – every one editable in MolDraw.

Sources

• Housecroft & Sharpe, Inorganic Chemistry, 5th ed., Pearson 2018 Textbook
• Atkins, de Paula & Keeler, Atkins' Physical Chemistry, 11th ed., OUP 2018 Textbook