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Author Topic: Is Liquid Oxygen magnetic?  (Read 2717 times)

Offline tommya300

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Is Liquid Oxygen magnetic?
« on: 29/08/2010 21:25:30 »
Why is it or why isn't it.


 

Offline Bored chemist

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Is Liquid Oxygen magnetic?
« Reply #1 on: 30/08/2010 10:25:49 »
It is strongly paramagnetic because (unusually) oxygen has a ground state with unpaired electrons.
 

Offline chemgeek

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Is Liquid Oxygen magnetic?
« Reply #2 on: 30/08/2010 11:24:06 »
Yes- the University of Nottingham did a demonstration of this on their open day with a test tube of liquid oxygen hanging from a string and a magnet  :)
 

Offline tommya300

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Is Liquid Oxygen magnetic?
« Reply #3 on: 30/08/2010 17:29:56 »
Can oxygen exhibit this property in the other states of matter?
 

Offline Bored chemist

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Is Liquid Oxygen magnetic?
« Reply #4 on: 30/08/2010 17:40:33 »
Yes, it's also paramagnetic as a solid and a gas.
 

Offline rosy

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Is Liquid Oxygen magnetic?
« Reply #5 on: 30/08/2010 18:20:53 »
Note that (molecular) oxygen is magnetic in the sense that iron is magnetic - it is attracted to a magnet.
It is not magnetic in the sense of being, in the bulk, a magnet in its own right... a vial of liquid oxygen won't attract a lump of iron to itself.

This is because in a paramagnetic substance such as O2, although the individual molecules may be considered as a bit like little magnets an overall magnetic field is generated only if there is an overall tendency for those magnets to line up in a particular direction. Soft iron can be magnetised (turned into a permanent magnet) by the presence of a magnetic field because those little magnets can be forced to line up and, once lined up, will remain aligned. Because oxygen's a liquid all the molecules are continually tumbling about and don't  stay aligned. 

It's possible (I don't know and haven't looked it up) that if liquid oxygen were cooled to a solid in a magnetic field a permanent magnet might result... but in any case as BC says the solid would be attracted to a magnetic field.

Although gaseous oxygen is attracted to magnets, the magnetic force per molecule wouldn't be strong enough to detectably enrich the oxygen in the atmosphere around a magnet in the face of normal air circulation, so it's not an important effect.
 

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Is Liquid Oxygen magnetic?
« Reply #5 on: 30/08/2010 18:20:53 »

 

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