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Name: Jeff
Status: student
Grade: 9-12
Location: WA
Country: USA
Date: Fall 2012


Question:
Are any gases affected by magnets?

Replies:
All atoms are affected by magnetic fields -- however, the macroscopic "magnetism" that you see with iron is because the atoms in those metals are all lined up the same way, so you get a big observable effect. With gases, the atoms are all oriented differently, so the overall "macroscopic" effect is basically nil. Magnetism is actually a very complex thing when you dig into it -- for more advanced information, you can read about "diamagnetism", "paramagnetism", and "ferromagnetism" (ferromagnetism is the commonly-known type).

In short, "technically" yes magnets affect gases. But in "normal" terms, gases cannot be magnetic the way metals can be.

Hope this helps, Burr Zimmerman


Hi Jeff,

No, for the overwhelming number of circumstances we usually find ourselves in when working with gases. Yes, for very few gases, but only under very specific circumstances.

Magnetic properties are attributed to materials that have ordered unpaired electron(e-) spins. These e- spins cause an orientation effect and a field is generated. This is almost exclusively a property of solids which allow for order and regularity of matrix.

Let us look at the usual instance of everyday gases: Most gases are not magnetic. O2 gas is a good example of a paramagnetic material, there are unpaired e-, but they are not ordered. However, when the O2 is cooled to 53K, it is an ordered solid and demonstrates magnetic properties.

In a landmark paper: Ariel Sommer, Mark Ku, Giacomo Roati & Martin W. Zwierlein , Nature 472, 201–204 (14 April 2011) Universal spin transport in a strongly interacting Fermi gas; doi:10.1038/nature09989 reported that Lithium gas when under sparse pressure at nanodegrees K and subjected to a plasma inducing current, the Li molecules did orient the spin of the electrons in a regularly ordered manner. Please recall that these conditions generate fermionic atoms, thus very remote from our usual gas conditions..

Thank you for this very interesting question! Peter E. Hughes, Ph.D. Milford, NH


Yes, paramagnetic gases are affect by a magnet. A paramagnetic gas is a gas that has an unpaired electron. This unpaired electron behaves as a little magnet. Two magnets can attract. Thus a paramagnetic gas will be slightly attracted to a magnet. Examples of paramagnetic gases are oxygen (O2), nitrogen monoxide (NO), and nitrogen dioxide (NO2).

J. S. Grell


All gases are affected by magnets, but maybe not in a way you mean. The important thing about gases for this question is that the individual atoms (or molecules) behave more independently than would atoms of a liquid or a solid, so we can get most of the answer just from the behavior of atoms.

Individual atoms respond to a magnetic field because the field changes the energies of some states. You won't notice this unless you shine light on them and measure what comes back carefully.

Some atoms are themselves little magnets, either because they have an odd number of electrons, or because of the way the electrons are configured. Atoms like this will be forced to move by a magnetic field that is not uniform.

Atoms with fewer or more electrons than protons (ionized atoms) will be forced to change direction if they move quickly through a magnetic field.

Tim Mooney


If they are ionized, yes. A magnetic field produces a force on charged particles. Typical gas molecules, such as oxygen or nitrogen are electrostaticlly neutral in their natural state. However, if the gas becomes ionized, meaning it looses or gains some electrons, then it will contain a overall charge and could be manipulated by a magnetic field produced by a magnet. We have a word of ionized gas, it is called plasma.

Ben Sirota


Yes. Any gas whose atoms/molecules have a magnetic moment will interact with a magnetic field – hence, a magnet. The “classic” case is oxygen (O2), but this is by no means the only example. If you “dip” a magnet into liquid oxygen, and draw the magnet out, the liquid oxygen will “stick” to the magnet. However, this is a demonstration that should only be done by an “expert”. Liquid oxygen is not a substance to be “fooled around with”. The effect with gaseous O2 has the same properties, but because of the lower density of the gas it is more difficult to observe – but it is still there.

Vince Calder


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