Short20151 min854×480

Paramagnetism of Manganese Salts 01

Brandon Curtis

At the Wikimedia Commons

About

I stained water with highlighter fluid, then dissolved manganese sulfate in it until it was slightly more dense than dichloromethane (DCM). The paramagnetic manganese ions are drawn to the 1" diameter cylinder N50 nickel-plated neodymium magnet.

I shot the video on a Canon PowerShot ELPH 100HS and processed it in OpenShot on Ubuntu 14.04. The audio is 'Reflections' by MK2, from the YouTube open source collection.

It always bothered me that paramagnetism was talked about but never demonstrated. This is just aqueous manganese sulfate in dichloromethane, which is much easier to work with (and see!) than the liquid oxygen example typically cited in textbooks! You could even do the demo with salts that contain ions with different effective magnetic moments, like cobalt chloride and iron sulfate, and/or the same ion in different oxidation states to drive home the mechanism. With the right magnet-containing sample holder, you might even be able to quantify the difference.

Note that in a glass container, the paramagnetic aqueous phase does tend to 'stick' to the walls; in a DCM-compatible clear plastic like polypropylene, the aqueous phase should remain as droplets for longer.

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Brandon Curtis
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